2000-2002 Silverado Rear Diff Partial Rebuild

[mrrsm]

Decided to use ACDelco Disks, Calipers and Ceramic Pads on the Front... and choose the AutoZone Duralast Top Quality Zinc Coated Rear Disks and HQ MAX Ceramic Pads. The New set of "Meaty" looking Parking Brake Shoes is from Raybestos, while the replacement PB Hardware Kit comes from ACDelco.

To avoid the requisite Clean Up and prep work drudgery ... I'm also going with ACDelco Re-manned "Pre-Loaded" Rear Calipers that comes with Newly Sand Blasted and Silver Coated Cast Iron Brackets already installed. I'm still waiting for the Driver's Side ACDelco Rear Brake Hardware to arrive next week (Which is Okay... because I'm on forced "Light Duty" temporarily anyway). Apparently, Amazon does NOT offer the Professional ACDelco Disk Brakes in PAIRS and the coming Driver's Side Caliper Unit is more expensive with the added in cost of them including the OEM Rear Ceramic Pads.

***My Sincere Thanks to @Mounce for recently clearing up a Worrisome Question I had about the Parking Brakes on my Truck!

 

[mrrsm]

The last of the ACDelco Brake Assemblies and Dorman sub-Parts finally arrived. The Final Rear Brake Clean Up, Parking Brake Cable(s) Installation and the collective Assembly, Testing and Disc to Break Pad "Wear In" will follow on. Strangely enough ...The Hard Copy GM 2000 Silverado OEM Shop Manual advises on Page 5-66 Paragraph #1 to:

"Burnish the Brakes by Making 20 Stops at 30 MPH using Medium to Firm Brake Pressure. Be careful NOT to Overheat the "breaks" (Misp?) while performing the Burnishing Procedure..."

Now THAT is a very interesting Disk Pad and Rotor "Break-In" Method which I've never known about from any past GM Brake Repair and Break-In Experiences. Here are the images of the last of the requisite repair parts and assemblies to arrive. This work begins tomorrow morning:

 

[mrrsm]

Hit a Glitch this morning... The Dust Shield Tins have to be Unbolted and Pulled to install the Damned Black Rubber Parking Brake Lever Booties. I LOVE this Damned Truck... So I might as well go Yard and pull the Rear Axles and replace the Axle Bearings with some Timkens. It follows to replace the Old Gear Oil and the two OEM worn Axle "C" Clips with a 'Beefier" pair from Yukon. I'll need to replace the Rear Diff Gasket with either some "New" Permatex Green Gear Oil Resistant Goo ...or maybe stick with using the Felpro OEM one... Any thoughts or recommendations?

Last but not Least, I'm replacing the OEM Rear Diff Cover Tin and Bolt Set for a Chrome one that can also be Filled or Topped Off from the BACK Side via a convenient access port. After a short delay until this coming Friday, 01/11/2020... once all of THIS stuff gets here, I'll get right back on the job. At this point.. I'll have to think up a Different Thread Title to cover all of this effort:



EDIT:

Ooops... Almost FUBAR'd this Order by getting ANOTHER OEM Brand Slide Hammer. I got Lucky and found THIS one among some Old Z-28 Parts Boxes with a Bearing Puller already attached. I'm still Ordering that Shakley "GoldiLocks" (3) Piece Set of Bearing Pullers... JIK the one I have for use on the Gen 4 F-Body Rear Axles turns out to be Too Small:

 

[Mooseman]

I prefer the original rubber diff cover gasket. It's pricier but allows reuse and no mess. The TB still had its original seal and I reused it when I changed the lube. No leaks. Also put one back on the Saab.

 

[mrrsm]

Cool... I didn't know "There is No 'Diff'..." between the Rear Axle 'Diffs" in the Silvies vs. the TB-Envoys-Saab vehicles... Yes? As per your suggestion, I found this one from ACDelco available on Amazon for around $20.00 with S&H included. I've ordered this item just now:

 

[Mooseman]

There doesn't seem to be one for the earlier trucks. I checked and they don't seem to interchange. My bad. In that case, I would just go with RTV.

 

[mrrsm]

I edited Post# 6 after getting the ACDelco version. Thanks for the update.

 

[Mooseman]

I looked at the closeup pic and it looks like regular flat cardboard.

 

[mrrsm]

You mean on the ACDelco one I just ordered? Oh well... At the very least I'll have a Nice Variety of Diff Gasket Options to choose from and some time to think about it B4 the Dorman 'Chrome Dome' arrives and needs to get bolted up to the Rear End.

I suspect that the "New Green Goo" from Permatex requires a thorough cleaning of both surfaces using a handful of Razor Blades and some Solvent. Then after applying this Stuff to BOTH to sides and mating them together while still wet (ever so lightly) there is probably a brief waiting period necessary afterwards to allow for the Silicone to cure before applying the the Final Torque Down in a Star Pattern over the (10) Chrome-Plated Bolts.

As you rightly mentioned in another "Unnecessary Thread" I was struggling with...(and graciously assisted by @Mounce) Had I seen THIS Guy's On Topic Video about another 2000 Chevrolet Silverado 1500 , ALL of my Questions about the entire pending work (including pulling the Axles) would have been Answered. The only issue this VOP presents that Makes My Skin Crawl is that he "Works REALLY Dirty" in ways that I NEVER will:

 

[mrrsm]

Just a few more things are coming on Friday to make the jobs of (1) Rust and Dirt Removal, (2) Differential Case Flange (Old Gasket) Cleanup, and (3) Diff Gear Box Re-Filling through the H-10 HEX Plug in the BACK of the Dorman Chrome Diff Cover ... ALL a little easier to accomplish:

 

[mrrsm]

Some of the Rear Differential and Rear Axle R&R Gear I ordered for Friday Delivery came in Late this Thursday Evening on 01/09/2020. Please Note: I tested the Thread-On smoothness of the Fittings on the Shankly (3) Piece Axle Roller Bearing Puller. They ALL Threaded easily onto the OEM Brand "Slide Hammer" Mounting Rod PERFECTLY... Just as illustrated in one of the attached images: (NOT Bad ...for ONLY $22.00 )

The Dorman Chromed Rear Differential Cover Plate is NOT made of "Thin Tin". Instead, it has been manufactured out of some VERY HEAVY Gauge Stamping that looks to be Flash-Chromed Mild Steel. It is fitted with a Friction Drilled Rear Filler Port, Tapped and Plugged Off via a Metric, (with an Mildly Magnetic Ferrite Insert in the base of the Threaded Plug). It gets tightened or loosened up via an H-8 Stainless Steel Plug that seals tightly with a Wide and thick White Nylon Washer-Grommet.

 

[Mooseman]

So that cover isn't a polished chrome, which is nice. And I also like the idea of that filler plug. What do you think its rust resistance is like?

 

[mrrsm]

The Whole thing looks like it is made out of the Same Stuff... Inside and Out. So it's probably pretty damned good at being Corrosion and Rust Resistant. It was NOT Coated in Light Oil right out of the Box and you cannot tell whether its is S/S ...or Chrome Steel from looking at the metal margins. I'm not even sure that it has any type of Chrome 'Coating" at all... but I did not want to give the wrong impression to our Folks that it was anything else... without knowing more about how Dorman makes these things.

This Lid is One, Heavy, Solid Piece of Stamped Steel... with maybe 'something else' thrown in for good measure into the Mix. You can't Chrome Plate Bare Steel without first treating the surface with an Acid Bath that includes a Zinc-Phosphate or Copper Coating component as well in order for the Chrome Bath to "stick" to during the Electrolysis Process. So having all of those Odd Layers would certainly discourage Rust; short of some kind of Impact Damage leading into the base metal and exposing the Steel to Air and Moisture.

If you look closely at some of those images... you can see that the 'Satin' looking metal has some 'contact smears' from being next to some other metal things prior to sale, without actually penetrating INTO the Metal exterior through any sort of obvious Extra Metallic 'skin'. And I swear... if I did not know better, I'd think it was made of somethings that is more like 304 S/S. I'll have to poke around and see if I can get some other opinions or videos about this thing. All I know is ...Nobody will be able to PAINT or Coat this Metal Diff Cover... So it would HAVE to be at least a LITTLE Rust Resistant, or they would soon not be able to sell this item if they turned Rusty Brown and got Gnarly in Bad Weather vs. the Ordinary Black Painted "Thin Tin" Coverings they also offer for sale.

We obviously have Very Mild Weather for most of the year down here in Florida, with the exception of the Tropical Storm Season. So a better Test Location would have to be done either up in the RUST BELT of the USA or way up in the Great White North when the Roads and Highways are Icy and have to be covered in Rock Salt, Sand and everything on them gets coated in Brown, Salty Slush.

Having that Outside Hex Drain Plug will encourage anyone who is ordinarily reluctant to Drain and Refill their Diffs to re-consider doing so when they no longer will have to remove that Rusty "Dough Boy Helmet" to do the job. Besides that... You can also use that patent Hex Plug Filler Port in order to Douse the Gear Box Innards with a Can of Spray Brake Cleaner if necessary.

Then ...either use a Manual Suction Pump with a Hose fed down into the very bottom of Diff Housing to get at all the loosened and dissolved Old Black 75W-90 Oil and Worn Metal Sludge. Or... if necessary ...run some length of Brand New White Cotton Clothesline Rope in through the same Filler Port to act as an Absorbent Material for a bit... then slowly pull that cord out and toss the whole mess into the trash. :>)

 

[Redbeard]

Easy way to check if the cover is stainless steel (300 series) is see if a magnet will take to it. If the magnet holds, it may rust, but if no attraction to the magnet she won't rust The 300 series of stainless is non magnetic. "Regular" steels and 400 series stainless steel both take to a magnet and both can rust.

 

[mrrsm]

Of course! Thanks @Redbeard for prodding my memory... I posted a Chart of these variations recently. To do this Simple Test... I first pulled the Metric H-8 (NOT Metric H-10) Diff Cover Filler Plug... but it has such a Mild Magnetic Field that it would NOT Stick to the Cover. Next I tried a Common Refrigerator Magnet and BAM! THAT one sticks and holds like GLUE. So Thanks... Problem Solved. THIS Cover HAS to be made out of Chrome Plated Mild Steel:

 

[Mooseman]

I wonder how feasible it would be to tap and plug the spot where there used to be a drain plug? Although it's probably better to open it up and get every bit of the old lube out, if it's done often, then it's not so bad.

 

[mrrsm]

I think they DO make a Mild Steel Bung with a 15mm Magnetic Drain Plug as a Kit... and this thickness of Diff Cover Steel would certainly support the addition...but you would have to know just how far out the Gears reach inside the Diff Housing to avoid having things 'clang' together near the 'Basement'. It is a Great Idea, though.

Okay... FINALLY.... The rest of the Parts, Pieces and Lubricant have arrived. This "Even Dozen" bunch of photos rounds off EVERYTHING required for this Job. Dammit.. I won't be able to tear into this Work until Sunday... Tomorrow is a Wash...The "Lil ' Woman's" Mandatory visit to the Beauty Parlor pre-empts THIS job while she is unable to drive:




And for any Trailblazer and Envoy Owners up in the Rust Belt with signs of Differential Oil Leaks on their Driveway Floors... THIS Amazon Customer used some the Permatex Gear Oil Gasket Maker to solve the problem of having Badly Rusted and Pitted Cover "Tin". He used THIS:



...and reacted by saying THIS:

 

[mrrsm]

Okay... "D" Day... (Uh... Differential Day) has FINALLY arrived and I'm intent on starting early enough to get the following broad topics completed and photo-documented. Meanwhile... Please enjoy in contrast to the Video in Post# 10 ... JIMMY from "1Road" performs this ' Sanitary Method' of ripping open 'The Pumpkin' on his Old, But Beautiful Truck to Change the Diff Fluid.

Much of what he covers will be unnecessary in my situation, since I'll be replacing the Diff Cover and Fasteners with New Chromed Parts. However, the processes I will be using are Spot On with what he does here and will become an excellent set of Diff Gear Oil Changing procedures, no matter what kind of Differential Gear Box hides under the back of YOUR Trucks and SUVs.

Here is a list of what needs doing Today:

** ALL GM OEM Torque Levels will be Applied as per the Hard Copy Shop Manual Instructions**

(1)Unbolt, Uncover and Drain Out the Old Differential Gear Oil into a Plastic Catch Pan.
(2) Razor Scrape the Diff Gear Box Flange and Spray Down the Interior with Brake Cleaner.
(3) Unbolt and Remove the Spider Gear Lock-Pin Fastener and Pull Out The Center Dowel Pin.
(4) Push the Axle Flanges INWARD and Magnet Probe-Remove the (2) Axle Retention "C" Clips.
(5) Pull out both Rear Axles and Slide-Hammer out the Pair of Roller Bearings and Outer Seals.
(6) Unbolt & Remove the (4) 18mm Bolts, the (L) & (R) Parking Brake Cable Brackets & Shields.
(7) Clean the Axle Tube Ends, Tap in the (2) New Timken Axle Roller Bearings and ACDelco Seals.
(8) Clean up the (2) Tin Dust Shields and Replace the Two Rubber Parking Brake Lever "Boots.
(9) Replace the The Two Dust Covers, (L) & (R) Parking Brake Cable Brackets & (4) 18mm Bolts.
(10) Inspect for Damage and then Replace the (2) Rear Axles & Insert the (2) New Yukon "C" Clips.
(11) Insert the Spider Gears Dowel and use the New Dorman 8mm Lock-Pin to secure the Gears.
(12) Install the New ACDelco Differential Cover Gasket, Dorman Chrome Cover and (10) Bolts.
(14) Remove the New Cover BACK H-8 Filler Plug and Fill the Diff Case with Mobile1- 75W-90 Oil.
(15) Later on, Check for Static and Dynamic Gear Oil Leaks via a Piece of Cardboard as a 'Reveal'.
(16) Insert the Parking Brake Cable Lever and Re-Build the Bracket with the HW Assembly Kit.
(17) R&R ALL Parking Brake Cable Assemblies insert the Cable Springs on the Levers & Brackets.
(18) Install the (L) & (R) Side Raybestos Parking Brake Shoes and ADJUST for Disc Contact.
(19) R&R Pairs of Rear Brake Caliper Assemblies with OEM, Brackets, Brake Pads & Brake Discs.
(20) Use the Tech 2 to Power Bleed the ABS and follow the Normal Brake Bleeding Procedures.

"If I can get through this List without Delay... it WILL be turn out to be... A Very Good Day! " :>)

 

[mrrsm]

This Work is Very Difficult to DO… Even if you are Thoughtful, Organized and have the Best Tools and Parts. I'll focus on writing about the Problems I encountered, How I Dealt with them and What YOU can expect if YOU decide to "Go Yard" on Cracking Open the Diff Pumpkin and Pulling the Rear Axles to get at Replacing ALL of the critical stuff BEHIND the Axle Stud Plates. THESE are Hard Won Lessons... With some helpful suggestions on What to DO to AVOID to SAVE TIME and EFFORT:

Because these segments are Content and Image Heavy… I’m Posting them in (4) Parts:

Part 1 of 4

Reaction (Thrust) Block.

After removing the 8mm Holding Bolt and the Center Pin restricting the "C" Clips from being removed... Late last evening, when I was at the point of re-installing the Two Rear Axle Shafts, I accidentally jostled the Diff Gears Innards and somehow managed to Dislodge the Reaction Thrust Block from its internal position in between the (4) Spider Gears of this Eaton G-80 "Locker". So I think that right about now, I could use some advice and help from @Mounce on the What the Best Way is to get that Thrust Block put BACK into the proper position.

As of right now… I've had to pull it completely out through the Oval Hole in the Eaton casement holding the Spider Gears. With so much of this work completed now, at the very last of it, I DO NOT want to FUBAR the Re-Installation of this component or have anything else fall out before I can put things RIGHT. Here are some images of these obscure areas that are involved:

 

[mrrsm]

Continuing on with Part 2 of 4 ...

(1) Spare Tire. if you are going to be able to have FULL access to the Differential Case... you WILL need to Drop the Spare Tire. This took me almost (2) Hours to accomplish because the Original Owner decided to JAM one of the Tire Cable Gear Box Rods INSIDE the Access Channel. Even with NOT having to deal with Excessive Rust... the Damned Thing was jammed up SO tight that it left permanent damage to the sidewall areas of the Spare Tire and scrubbed ALL of the Black Paint off of the Cross Mounted Steel Tubing:



(2) Wind. I've NEVER changed the Oil in ANY Vehicle without having the Wind throw 50 MPH Gusts in my face at the very moment the Drain Plugs came out, Gear Oil? IT'S WORSE! When I cracked the Seal on the Lower Cover, the Wind suddenly picked up and I had to resort to Lifting and Holding up the Drain Pan close to the opening. Bad Idea. Gear Oil weighs a TON when one hand and your arm is fully extended as the stuff gushes out. Gear Oil? SPILLED EVERYWHERE! Solution? Cut a Large Section of Cardboard and wedge it Under the Chassis as a Wind Shear Block from the dominant direction and the Gear Oil Draining will be more manageable:



(3) Tools. The Milwaukee M12 FUEL Mini-Impact Wrench works amazingly well with the GearWrench Impact Grade Wobble Sockets (13 mm for the Diff Pan Bolts and 18mm for the Parking Brake Brackets. Same for the M18 1,400 Ft Lb Big Brother Unit... But Remember... At First... Use the Lower to Mid-Power Battery Settings on BOTH Tools FIRST or you will risk Snapping Off Small Fasteners:



(4) Gasket Removal. If you want to save a substantial amount of time when scraping and cleaning Old Gasket Material off of the Diff Case Flange and Cover if needed... DON'T HOLD THE BLADES WITH YOUR FINGERS AND RISK SLIPPING AND GETTING CUTS. Spend a little 'Baksheesh' and a buy pair of the small Hand Razor Blade Scrapers that will SAFELY hold the Blades at the end of a sturdy and EZ2 Grip Handle. Then WAIL AWAY to your Heart's Content without any Worries. After that... Use a Ryobi Battery Powered Drill with some Very Fine Wire Wheels and then De-Rust, Polish and Dress Up all of the Flange surfaces:



(5) Roller Bearing Puller. You do not have to remove the Outer Axle Seal separately... unless you want to AS LONG AS THE BEARING REMOVAL TOOL FITS THE BACKSIDE OF THE BEARING RACE PERFECTLY. The problem is that I tried using the Mid-Size Shankley Bearing Puller from the Kit and a LONG 10 Lb "OEM" Slide Hammer ...and I wound up having an uneven distribution of Yanking FORCE that Destroyed the Outer Bearing Race when the Puller has a grip on the Roller Bearings and Yanked them out, Destroying the Outer Bearing Races and threw Roller Bearings all over the Driveway. Ultimately, I had to choose to "Modify" the Oversized Puller from the Shankley Kit by using my Bench Grinder to remove about 1/8" from BOTH sides of the Tool in order to get the right distribution of force FLUSH up against the Inner Bearing Race Flange before I was finally able to "Slide Hammer" the FUBAR'd Bearing Race remnants out of the Axle Tubes. ANY other Mis-Positioning of the Shankley Bearing Puller will JAM the Bearings Races inside of the Axle Tubes!



More to Follow...

 

[mrrsm]

The Next Part is ... 3 of 4...

(6) Rear Axle Removal. This is where it will Pay Off if you Slow Down and approach this part with CAUTION. By now... You should have Used almost a Full Can of Spray Brake Cleaner to De-Gunk all of the Black Greasy leftovers on the ALL of the Gear Surfaces and Flushed out the insides of "The Pumpkin" to remove all traces of Old gear Oil and Metal Residue.

If you decided NOT to remove the Drive Shaft... You'll have to Plug in the Ignition Key to be able to place the 4L60E into the "Neutral" Shifting Position to be able to stick a Large Flat-Blade Screwdriver into the "U" Joint in front of the Differential and be able to SLOWLY Rotate "The Works" and get the Eaton Housing positioned where you can see the Large Center Pin ...and have access to its (8)mm Locking Bolt. BE CAREFUL when unbolting this Small Fastener, as they have a Reputation for Snapping Off!



Once that Bolt becomes loose you'll either have to use your fingers or an (8)mm Box End Wrench to coax it all the way out. Once free... You should place one hand in front of the Heavy Dowel Pin so it does NOT drop down suddenly out of the Center Thrust Block and Knock Out your Front Teeth...Just Gently Press it out from the back side and it should slide right on out.

Then... Push IN on BOTH Rear Axles in order to expose the Two Locking "C" Clips. Use a Strong Pencil Magnet to work them out of their hidden cavities. After that... Slide the Axles out WHILE BEARING THEIR WEIGHT CLOSE TO THE EXTERNAL GEAR OIL SEAL ON THE ENDS OF THE AXLE TUBES. Wipe-Spray them both down with Brake Cleaner and after inspecting them for Damage on the Teeth and Roller Bearing Surfaces... find a Safe Place to stand them both on their Flange Plate Bolt Ends where they will NOT get knocked over. Examine the "C" Clips for Wearing or Grooving and REPLACE them if ANY Damage is observed. The images below WILL show you what Bad Wearing looks like on those Clips. I'll replace THESE with the New Yukon Brand "C" Clips:



(7) Installing New Roller Bearings. Right Off The Bat… BUY A PROPER ROLLER BEARING INSTALLER KIT. Unfortunately, I wound up using a combination of a GM Atlas (circa 2000) Engine Harmonic Balancer Puller Tool sub-segments (the OD was slightly TOO BIG after getting the initial insertion of the Timken Bearing into the Axle Tube and then it got JAMMED inside. I finally had to Gerry-Rig a long 10.9 Hardness Bolt and some 12 X1.50 Nuts along with some Pieces of Scrap Steel to FINALLY be able to hammer in both New Timken Axle Roller Bearings a little at a time until they were ALL the way up to their stopping ridges inside the Axle Tubes. WHAT an Effing PITA!

Once the 'Chassis' are seated in deep inside the Tube Ends, the Installation of the Axle Gear Oil Seals is VERY EZ2 Do... Grab a Chunk of 2" X 4" Wood ...inset the Seal... Get it LEVEL and EVEN all the way around and Gently Tap it In Place. After squirting some Fresh Gear Oil inside of and over the Roller Bearings just past the Seal Lips... You're DONE with the Bearings and Seals R&R Portion of the Job:

 

[mrrsm]

And Finally... Last for this (4) Part Series...

(8) Parking Plate Bracket R&R. Spend the Money... Get the ACDelco Brake Rebuild Kit along with getting the Pair of Dorman Parking Brake Bracket Lever Arm Black Rubber "Booties" and the assembly will be a BREEZE. Use a Wire Wheel to Remove Surface Rust and once everything is assembled with some Lithium Grease packed up inside of the internal Brake Shoe Adjuster Parts... Then Apply some Blue Painters Tape to the Park Brake Shoe Adjuster ...just to keep the New Hardware from falling out during re-assembly on the Axles. Don't Forget to Wire Wheel Clean those (4) 18mm 'Diamond Hard' 10.9 Fasteners Thread Lines. AND... Whatever you DO... AVOID BREATHING THE OLD, DESICCATED LOK-TITE DUST FILLING THE AIR AROUND YOU FROM THE WIRE WHEEL ACTION. Use some New Lok-Tite on those Bolt Threads and then tighten them all down to 100 Ft Lbs of Torque.

One last thing worth mentioning here is a Neat Trick to Speed Up the Removal of the Parking Brake Cable from the Inside Bracket Support:

Use a 1/4" to 1/2" vernier S/S Hose Clamp by positioning it loosely around the Holding Fitting on the inside of the Bracket. Then Tighten it Down REAL Hard ...Enough to collapse ALL of those Weird Locking Tines. After that... Loosen and Remove the S/S Hose Clamp and that PITA-to-Remove Brake Cable & Housing will slip RTF Out of that Bracket ...like Butter. :>)



I'll need a Day or so to physically recover due to tweaking my Old Spinal Injury. But in the mean time... I'm using the Blue/White FelPro Diff Cover Gasket as a "Throw Away" (I'll be using the ACDelco One very soon) by having it tucked up under the New Chrome Cover. It's held in place with (3) of those Shiny, Hard Chromed (13)mm Bolts. I don't want any of those High Carbon Steel surfaces to Rust Up in the Damp Florida Air or get drenched from any Hellacious Surprise Winter Thunder Storms before I can get back to working under the Truck again. I look forward to hearing from @Mounce about the Thrust Block Issue and I'm not likely to tackle working on it for at least another Day or Two from now.

 

[mrrsm]

Okay... I poked around looking for some illustrative Views of this Damned Thing... and I THINK I've got it sorted out now. Here is an Image of a Used Eaton Rear Differential that shows the Position of that "Thrust Block" ...as Installed and 'pinned':



...and HERE is the Actual Item I just located and bought as a Brand New Eaton Thrust Block identical to the Original Part that Fell Out of my Differential ...JIK I FUBAR'd that Damned Original Part:



I just cleaned up the Errant Part and took some 360 Degrees Images. The Old One not only has some subtle circular wear patterns one the surfaces making contact with the Four Spider Gears...but it also has some 'nicks' in on the un-radiused right angle margins in spots that makes me think I may 'crunched' it into the Spider Cluster a bit and this caused this damage. I'm going to wait a week until the New Part arrives... just to be on the safe side. After all... A Brand New Part should be Better than an Old Part as long as it is a GM OEM Component and I'm in No Rush ...right now:




And perhaps the MOST Confirming Evidence of HOW this Thrust Block fits inside of the NON-Limited Slip Mechanism (It's a LOCKER... NOT a SLIPPER) comes directly from EATON as "3D Exploded Diagram Movie" in which (when played at 1/2 Normal Speed... you can actually See INTO all of the Moving and Non-Moving Parts that make the GM G-80 MLocker Differential Work So Well:

 

[Mounce]

Yeah I know nothing about said block lol. Looks like the pin goes through it? I'd have to just play with it till the correct orientation is found if it were me and I'd knocked her loose in the case that I couldn't find a diagram or something to go off of.

 

[mrrsm]

I think I've got "The Hang Of It...." Now. When I'm up to filling in my 'Mechanic's Repair Dance Card' for some more activities on the Truck in a few days... I'll sort that Damned "Chunky Steel" Thing Out. Thanks again for touching base with me on this issue.

EDIT and Update @ 10:07 PM:

Check out THIS Video... In this situation, the Helpful Dude is working on his GMC Sierra 1500 sporting an EATON MLocker Differential that looks just like mine. He demonstrates how to re-position things to gain better access to the 'innards' through that fairly small Side Access Hole in the EATON Shell to pull and replace his "C" Clips retaining the Truck Axles.

He Rotates the Ring Gear and the Body of the Centrifugal Clutch to the point where you can CLEARLY see where that Steel Thrust Block Component is normally located.

I think if I can mimic what he does and re-position mine in similar fashion... I'll be able to mess around with that centrally located Heavy Metal Unit and carefully work it back in between the (4) Spider Gears and NOT cause any Damage to the more delicate components nested inside of "The Pumpkin".

...and in THIS one... Mike from 1AAUTO shows a similar scene with some closeups of the Thrust Block at hand. He also covers the R&R of the Axle Bearing Replacement using his "Slide Hammer" and Bearing Puller. Between these two Vidz, my confidence is high that I'll be able to get into that area and solve the problem. However, I'll Have to raise the back end up quite a bit more to be able to see inside of the Oval to work:

 

[mrrsm]

The Brand New GM "G80 MLocker" Eaton Differential Thrust Block that bears the GM P/N 12471396 on the OEM S&H container just arrived. I Photo Memorialized the appearances of the New Part vs. the Old Part while examining and comparing them "Side by Side" and searching for any discrepancies in obvious Wear Marks on the Old One vs. the New One, looking for signs or lack of any problems with their common appearances and measured dimensions.

There are some very subtle artifacts of Normal Wear on the Old Part, but also SOME NOT SO SUBTLE Abnormal Damage that perhaps was caused after both "C" Clips suffered excessive wearing and having the affect of somehow allowing DEEP SCORING to happen inside of the Center Pin Bore. The fact that the otherwise trapped "C" Clips had too much lateral freedom of movement seems to finger them as the Culprits causing the damage inside of the Old Thrust Block. Right now... I'm thinking about Replacing that Large Center Pin, right along with a Whole New Set of Spider Gears, just to be as Complete and Tidy about doing this unusual Repair as possible...before "Sealing Up The Pumpkin".

Tomorrow morning, I'll give it my Best Shot at practicing with installing the Old Thrust Block a few times before attempting to put the New One inside of the Eaton G80 Innards. If I decide against replacing the Old Spider Gear Set, I'll move right ahead with putting in The New Thrust Block, The Old Center Pin, The New Dorman 8mm Fastener and The Two New Yukon "C" Clips holding in the OEM Axles. Lastly, I'll close it all up inside by bolting on the New Chrome Steel 'Pumpkin Helmet' over the ACDelco Flange Gasket and fill it up from the Convenient 'outside' H-8 Plug Port with Fresh Mobil1 75W-90 Synthetic Gear Oil. If everything goes smoothly, I'll finish the remaining (L) & (R) Rear Disc Brakes Installation as well. I've dropped the (14) relevant Images taken of this 'Thrust Block Side-By-Side Comparison' into its own Album in my "Flickr-Bucket" ...as linked below:

https://www.flickr.com/photos/126111508@N07/albums/72157712699445326/with/49395626231/

 

[mrrsm]

Okay... After even MORE Research, I stumbled upon something that could be meaningful for ALL Owners of Trucks that have the GM Eaton G80 "M" Locker Differentials. ( The "M" stands for Mechanical vs. "E" for Electro-Magnetic):

I found a Forum discussion that focused entirely upon "What Gear Oil Should Be Used in Centrifugal-Locking Differentials?" The dialogue went on describing that even though the Mechanical Lockers DO have Textured Steel Plates in their Axle Lock-Up Designs... USING NON-SLIP ADDITIVES CAN ACTUALLY INVITE FAILURE because they are NOT the same Technology as Limited Slip (LSD) Differentials. This exploding view image Illustrates the presence of these Steel Plates built into the design of the Eaton G80 MLocker:



The Problem that comes with this reality is that MOST Heavy Weight Gear Oils invariably have the Non-Slip Additive Pre-Mixed in the Bottles. So I was very surprised to find out that My Choice of Mobil1 75W-90 Gear Oil was WRONG because it DOES contain a Limited Slip Additive.

One Forum Member advised that the ONLY 'Spot On' Brand he could find that met the GM-EATON Gear Oil Use Criteria is THIS Very Expensive AMSOIL Gear Oil. So I ordered (2) Bottles last night that are supposed to arrive sometime today:


Also... after confirming the Axle Spline Count (30) for my Truck Diff...



...I decided to 'Pull The Pin' to get the YUKON GM Eaton MLocker Spider Gears and Dowel Pin Kit. This Saved me around $63.00 vs. what the SAME Kit costs over on eBay:



For Owners of Trailblazers and Envoys ... Here is some Great Information on Re-Building the GM Eaton G80 MLocker Differentials under Your SUVs:

Rear Axle G80 Differential Rebuild | offroadTB.com

offroadtb.com

 

[mrrsm]

The Yukon Differential Spider Gears, Dowel Pin, Washers and Thrust Block Fastener Kit and (2) Bottles *** Correction (3)*** of Amsoil Gear Oil ARRIVED this morning. Wind and Weather will push this work to Sunday January 19th, 2020 or the day after. Here are some suggestions regarding Ordering Differential Parts via Amazon:



The rest of the images of the YUKON Spider Gear Kit can be seen on my "Flickr-Bucket":

https://www.flickr.com/photos/126111508@N07/albums/72157712699445326

(1) If you have your Diff Disassembled and cannot confirm the Spline Count for your particular Year- Make-Model of Truck or SUV... Stand One of the Axles on its Tire Bolt Flange Cluster and after using Brake Cleaner Spray, thoroughly clean out the End Axle Gear Teeth. Then... Take some Clear Digital Images so that you can sit down at your computer, Drinka-Cupper... and then Zoom and View your images while carefully Counting the Number of Axle Splines for comparisons with the various Yukon Diff Spider Gear Kits available On Line.

(2) Yukon offers quite a few Diff Spider Gear Kits that get sold off of the SAME PAGE, so Double Check what your Particular Diff Stats are and be certain that the Proper Kit matches your On Screen Selection as it is very easy to select the Wrong Kit. Here is the Reference Chart I used for confirmations:



...and it NEVER hurts to get Feedback from a Fellow GM Truck Owner (especially one with the Same Year-Make-Model Truck) who actually has Hands-On Experience with Buying, Installing and then Reporting Back about his/her Experience with these YUKON Spider Gear Kits:



(3) When your New Yukon Kit arrives... BEFORE opening the Purple and White Vacuum Packed Polar Bear Cardboard shipping plate... COUNT THE INTERNAL SPLINES of the Spider Gears to be certain they Match what your Axle Images show...and if things look incorrect...this will simplify making any Returns (RMAs) of Un-Opened Packages. Check the Shipping Box End to ensure that the Kit Specs match everything about the Differential for your particular applications.

(4) Use Spray Brake Cleaner to remove the New Grease and any Manufacturing Metal Residue and S&H Detritus before attempting to install them. Avoid Oiling these Gears and Washers prior to installation, as it will make the process of fitting things together that much harder if they are Too Slippery and the Concave Washer separate from the Spider Gears while being manipulated in close quarters. Once installed... you can then generously douse the Diff Spider Gears prior to wiping down the Diff Case Outer Flange with Brake Cleaner. Then install the ACDelco Gasket, close up the Diff Back Cover with (10) Bolts and fill the Diff reservoir with Amsoil 75W-90 Gear Oil.

 

[NJTB]

I had no idea that anti slip could be harmful to the differential. Same as you, I was going to get 2 bottles of the Mobil 1 75-90 gear oil when I change mine in the spring.
I did change the front differential with it.

 

[mrrsm]

The key thing here is that the GM Eaton MLocker is NOT a Posi-Traction Design. Here is a link to that discussion and why Limited Slip Additives should not be used in them:

https://www.gm-trucks.com/forums/topic/183167-g80-gear-lube-eaton-phone-call-today/

I was very surprised to find out that while GM has used the Mechanical Locker G80 designs in their vehicles for around 40 Years... NO other Automotive Manufacturer has employed this type of Centrifugal Force Differential Locking Mechanism. The other important and interesting thing is the mistaken impression I had about 4WD Vehicles invariably performing BETTER than 2WD in ALL conditions of Slippery Surfaces on either one side or the other. This videos educated me to the contrary; again with some excellent 3D Operational movement and via a GM Experimental Road Test Comparison demonstrating the How the Eaton MLocker behaves under adverse conditions, versus other Truck making companies NOT in possession of this Eaton Mechanical Device:

This video from Eaton shows precisely How it Works (and FINALLY showed me how to position that bizarre Thrust Block inside):

In this GM Dealership Demo ...ostensibly narrated by "Mr. Donut"... He shows how QUICKLY the Eaton MLocker responds to differences in the rotational speeds of the Left and Right Axles:

Somewhere on GMTN is a Thread posing the Question, "Does anyone take the GMT-800 Trucks Off Road?". Perhaps this 2WD vs. 4WD can answer that question and show a way to do that under mild OR conditions... as long as the Eaton MLocker is involved:

 

[mrrsm]

Progress Report:

@Mounce was right again about having to wrangle with that GD'ed Brand New Thrust Block for around an Hour... but after using an 'Old Jedi Mind Trick' and Spock's 'Vulcan Nerve Pinch', I FINALLY managed to maneuver it slowly back into its correct position. Also... The Two Yukon "C" Clips holding the Axles in place are a PERFECT Fit as a replacement for the GM OEM version:



This is Important...

I re-examined the Original Dowel Pin and its 8mm Fastener and found significant problems with BOTH. The 10.9 Hard Security Pin holding that Dowel Pin in place looks like it was trying to 'wallow out' the Hole through the Pin. The damage to BOTH components is obvious. The metal of the Dowel Pin that is meant to keep the Axles and the "C" Clips hidden under the (L) & (R) Flanges is obviously Machined Steel with close tolerances.... But NOT on the Drilled Through End.

THAT Cross-Drilled Hole is situated VERY CLOSE to the Edge-End of the Pin ...and looks like it was 'giving way' a bit because of the inside of the Heavy Dowel Pin Pounding against the outer smooth portion of the 8mm Restraining Bolt. THAT Bolt has a Groove worn into its Shank... and areas of hard contact have removed the "Blueing". These are Bad Things to have happen inside of a confined space with Heavy Axles, Spider Gears and a Massive Chunk of High Grade Steel nested inside constantly whirling around in Forward and Reverse. Just know... There is something very physical ,dynamic and mechanically wrong here at play:



It seems very possible that in time, either one or the other of these two things might fail after receiving enough Impact Wear and Tear. You can judge for yourself from observing the photo. This obvious damage may shed some light on why SOME GM Eaton G80s have acquired the Nick-Name "GOV-BOMB" after inexplicably "Grenading". I think that replacing the Dowel Pin, the 8mm Fastener and the "C" Clips should probably get serious consideration during Regular, Scheduled GM OEM Differential Gear Oil Changes... Just to be on the Safe Side.

Moving on... If you decide to get the Dorman Chrome Plated Cover ... Shine on the idea of getting any After-market Chrome Bolts. I discovered after-the- fact by removing the Old Cover and OEM Bolts that whoever serviced the Differential for the Original Owner in the past...had Cross-Threaded THREE of the OEM Bolts into the Diff Case. This caused no damage to the 10.9 Hard 13mm OEM (10) Bolts... but when replacing the OEM Fasteners with those After-Market Chrome Plated Fasteners, they almost destroyed themselves when I back them out.

Stick with the OEM Fasteners and an ACDelco Diff Gasket. After dressing up the Old Bolt Heads and Thread lines with a Wire Wheel (or using some GM New Ones).. add some Lok-Tite just prior to threading them in. Then start the first of two Star Pattern Bolt Tightening passes with your Torque Wrench set at 20 Ft Lbs.



More Work Follows Tomorrow Morning...Tuesday, 01/21/2020

 

[Maverick6587]

@MRRSM Thank you for another wonderfully detailed post! I am actually planning to change the front and rear diff fluid in the next few weeks on the 07 97x. While I am there I also plan to swap out the rear axle bearings and a transfer case fluid change.

The parts and tools list is always great. I totally forgot about that axle bearing puller. I need to just buy a kit since I need to put a new axle in the 06 97x to handle more HP (leaning toward a Strange S60).

Depending on free funds, I might do the spider gears as well. I still haven't even had time to do a compression test on the engine to see how good of shape it is in with 230k miles on it.

 

[mrrsm]

There was a 40 Degree drop in the ambient temperature down here in the last 48 hours accompanied by some pretty high winds. These weather conditions would be NOTHING for our GMTN Members living in the North. But for those of us who dwell year 'round in the Sub-Tropics and not accustomed to anything less than 70-80 Degrees, it does takes a bit of getting used to. If the wind dies down by this afternoon, I'll get back to working on the task of finishing with a complete Installation of the Rear Brakes.

Yesterday, I neglected to mention some things done to ensure the Best Application of Thread Locker on the 10.9 Bolts holding the Parking Brake Cable Brackets to the Axle Tube ends.. Permatex ORANGE Extra Strong Loctite seems the Best Choice because this stuff matches the characteristics of the Thread Locker used by GM during OEM Installations. I used the same stuff to secure the (10) Bolts on the Differential Cover. If the need arises to use THE Strongest Bolt Security in other places on the Truck... I have a BIG Bottle of Loctite #242 on hand:



I used a VERY Small amount of Mobil1 75W-90 to double check the New Rear Axle Roller Bearings and lube them thoroughly before inserting the (L) & (R) Rear Axles. The remaining Differential Fluid pumped inside the Diff Reservoir is Amsoil Severe Gear Full Synthetic 75W-90 Gear Oil:



I was surprised to find out that I didn't own a decent set of Line Flare Wrenches. Amazon carries the Geardrive Complete Set of SAE and Metric, Drop Forged, Chrome Vanadium Flare Wrenches. At a price of Fifty Bucks, this Kit might seem expensive, until you see just how many different kinds of Flare Lines these Tools can handle. I also ordered the Kit because I want to avoid damaging ANY Brake Line Fittings while installing the Brake Lines onto the New ACDelco OEM Full Caliper Assemblies:



And finally for today... After the last few days of climbing all over and under this Truck, I'm tired and not the least bit interested in doing so in order replace the Brake Fluid in the Master Cylinder and run around to all of the Brake Lines and Brake Cylinders-Calipers a Dozen Times. So I'm solving this issue by using a GM Model of The Motive Pressurized Brake Bleeder.

This Tool gets fitted to the Master Cylinder Cap location and assisted by an Allstar Magnetic Brake Fluid Catch Bottle... I'll simply Crack Open the Brake Bleeder Valves and follow the "Right Rear, Left Rear, Right Front, Left Front" Brake Bleeding Scheme to evacuate ALL of the Old Dot-3 Fluid and replace it with Fresh, ACDelco DOT-4 Fluid. I am expecting the delivery of these two devices and fluid this afternoon:



Later on, I'll use the "GYMKO" Tech 2 Scanner to activate the ABS unit and exercise it several times to ensure that No Air or Old, Contaminated DOT-3 remains hidden inside of the Unit. Then I'll Bleed the Entire System one last time.

Weather permitting... More work follows...

 

[mrrsm]

@Maverick6587 ...About replacing those Spider Gears... Even though I got the Complete Yukon Differential Spider Gears Kit (at a very nice $62.00 Discount) ... I wound up using ONLY the Dowel Pin and the 8mm Fastener because, while the Smaller Spider Gears CAN be extracted through the Small Port in the Thrust Block Side of the Housing of the Differential Carrier, the Two Axle Spline Spider Gears on either side of the case interior ... Are TOO BIG to fit through that hole.

The only way to completely replace the Spur Gears Set would be the added difficulty of first removing the Two Side Bearing Caps after unbolting the (4) Bolts and then prying the Eaton Carrier completely out of the "Pumpkin". After that, the Centrifugal Mechanisms in the back of the Carrier would ALSO have to be removed (On The Bench) in order to have enough access through that Larger Oval Opening to reach in and R&R the Entire Gear Set .

If it comes down to doing so much additional labor, then replacing the Side "Friction" Plate Packs of the Eaton Carrier would also be very wise. I examined the Differential Hypoid, Ring and Spider Gears of my Differential ...very carefully ...and found no damage to any of them, so no Preemptive R&R was necessary during my work. The OTHER Damaged Components I mentioned in Post#32 DID need replacing.

 

[Maverick6587]

I have never removed any of those gears before, we'll see how they look though and go from there.

Is it safe to spray brake cleaner into the pumpkin, the axle shafts, and into the differential itself, to remove all of the black goo? I just wiped everything I could reach with a lot of rags when I changed the diff fluid in the 06' 97x. As I wasn't 100% sure it would/wouldn't ruin any components inside.

 

[mrrsm]

Yes... Spray Brake Cleaner is more than adequate. With the Vehicle properly supported on Jack Stands...you'll have to rotate the Eaton Carrier around 360 Degrees using the Drive Shaft in order to gain access to all of the "Gunked Up" Gear Teeth...and then use "Blue" Scott Towels ONLY to avoid leaving fibers on the Gears...which should be avoided if possible when dipping and soaking up all of the "Mung" decorating all the Gears and casement that the Spray Brake Cleaner will dislodge and drop down to pool inside of the Lower *Pumpkin*.

These components are made of High Carbon, Hardened Steel... so they can take as much Brake Cleaner as you can throw at them as there are NO Rubber or PTFE (Poly-Tetra-Fluorine-Ethylene) or Teflon Brand Seals inside that area...until you get to the Axle Shaft Seals on the Outer Tube Ends. Remember... You'll have to put the Key in the Ignition and turn it to set the Shifter Handle in NEUTRAL... Mind how long you leave it in there in the ON-RUN Position... lest your Battery Goes DEAD after an all day effort.... (Ask Me How I KNow)

 

[mrrsm]

More Progress (Almost Done):

I've completely Installed the (L) & (R) Parking Brake Shoes and Hardware, Installed the New ACDelco OEM Caliper Sets and Duralast HQ Ceramic Brake Pads with CRC Brake Lubricant. With Brake Longevity in mind, I used the Duralast "Z-Lock" Zinc Coated Rear Brake Discs. I should mention that using the Pre-Assembled ACDelco OEM Caliper Units makes the job move along much quicker and with a much better outcome.

Tomorrow... I'll perform the Pressurized Brake Bleed using ACDelco's OEM DOT-4 Brake Fluid and and purge the Used DOT-3 Brake Fluid. After using the Tech 2 to clean out the ABS Unit, I'll perform 'Four Square' 2nd and 3rd Pressure Brake Bleeds until all Wheel bleed Clear and Air Bubble Free. Last on the List, I'll finish with installing all of the New ACDelco Park-Emergency Cables along with the New ACDelco OEM Parking Brake Pedal.

I took nearly (60 ) Images today of all this work and dropped them all over on my "Flickr-Bucket":

2000 CHEVROLET SILVERADO REAR BRAKE JOB

These Images show the Complete Replacement of the Rear Brakes on my Y2K Silverado. I used Duralast "Z-Lok" Rear Brake Disks and HQ Ceramic Pads. I also used ACDelco Complete OEM Rear Brake Calipers and Rear Axle Seals. I installed Timken Rear Axle Bearings.

www.flickr.com

 

[mrrsm]

Okay... The Pressurized Brake Bleed Procedures I used and completed are well documented here:

How to Perform a Pressurized Brake Bleed on ANY GM Vehicle

I thought it would be a good idea to break out this “Pressurized Brake Bleeding Procedure” from the other Brake Repair Work involved with my 2000 Chevrolet Silverado 1500 Long Bed Truck. I think this Procedure stands out from all others because it is THE Fastest, THE Easiest and THE Most...

gmtnation.com

The Imagery of this Work can be seen Here:

How to Pressure Bleed Brakes on ANY GM Vehicle

How To Pressure Brake Bleed ANY GM Vehicle.

www.flickr.com

Today, I ordered the ACDelco Professional Series of Front Left and Right Brake Caliper Sets to arrive here on January 28th, 2020. I will complete the replacement of those Units...noting that while Pricey at around $90.00 per Front Axle... these are the Heavy Zinc Coated Variety of the covered-protected Cast Iron Caliper Bodies.

The "Plain Jane" ACDelco variety is also available on Amazon for around $60.00 per Front Axle ...again...with NO BRAKE DISCS or BRAKE PADS included with ANY of these ACDelco Kits. (I've already acquired the ACDelco OEM Front (L) & (R) Solid Platters and the GM OEM Ceramic Brake Pads):



More Front Brake Work will Follow on ...and Finish This Project... Although I have been considering replacing the Two Front Wheel Bearing Hubs right along with the Front Brakes... Hmmm.

EDIT:

Oh What The Hell... I Talked myself into it... Detroit Axle has what looks like a Decent 2WD (6) Lug (L) & (R) Hub Set ...and Dorman has the New Three Bolt Sets of Fasteners available, too:

 

[Maverick6587]

@MRRSM I have those Detroit Axle front hubs in my 06. They've been on for about 6 months and I haven't had a problem with them at all! You can't beat that price and warranty.

 

[mrrsm]

Thanks for this 'Mechanical Encouragement'... I've been reading and monitoring your posts with interest and @Mooseman 's in particular regarding these Detroit Axle products in general and married to my own previous experiences... my confidence is very high that they will do well. Other members have added to this discussion (@Mounce and @littleblazer) in other related threads and their ideas and suggestions have also been very informative as well.

I have prior experience with changing out the Right Front Wheel Hub on my son's 2003 Chevrolet Silverado 1500 as documented in this Thread... but to be as comprehensive on this one as possible...I'll take additional images and record the jobs on my Blue Truck in detail :

SOLVED! - 2003 Chevrolet Silverado 1500 (Grinding Noise @ Right Front)

EDIT: Even though I got Very Lucky in Diagnosing and Solving THIS PARTICULAR PROBLEM... The number of things that can go "Bang and Bump and Grind" under our vehicles is HUGE... So Please.... Start with viewing Drew's @MAY03LT "One Over The World" Suspension Noise Diagnostic Video to get a...

gmtnation.com