NEED HELP 2002 Envoy SLT 4WD - Oil Pan Removal / 4WD Delete

slidr

Member
I need to replace the timing cover so in order to get the oil pickup tube bolt undone, I'm either going to try and drill a hole in the oil pan to access it, or just wind up dropping the oil pan.

If I go with the second route, I plan on not reinstalling whatever 4WD components I can get away with since I don't need it (and really never have; car is on borrowed time with 260K miles on it).

So can I just remove the halfshafts and intermediate shaft and plug the differential hole with a cap or something?

Also, this is what I've found for the oil pan removal:

  1. Remove the A/C compressor bottom bolts and move it aside
  2. Remove the oil level indicator and tube.
  3. Raise the vehicle..
  4. Remove left and right front tire and wheel assemblies.
  5. Remove the engine protection shield mounting bolts.
  6. Remove the engine protection shield.
  7. Remove the steering gear crossmember, front.
  8. Remove the left and right wheel drive shaft.
  9. Remove the front drive axle clutch fork assembly.
  10. Disconnect the prop shaft from the front axle pinion yoke.
  11. Remove the oil pan drain plug and drain the oil.
  12. Unclip the transmission cooler lines from the engine block.
  13. Remove the front differential bolts and set aside the front differential.
  14. Remove 4 transmission bell housing bolts that are attached to the oil pan.
  15. Remove the remaining oil pan bolts.
  16. Place 2 oil pan bolts in the jack screws on the oil pan and tighten evenly to release the oil pan from the engine.


From what I've read online, this is around a 10 hour job. Seems to me it should take no more than 4 hours, what am I missing, what is more time consuming than I am imagining?

Thank you.
 

Mooseman

Moderator
Check for my threads on this specific job in the FAQ. 10 hours is actually in a nice shop with a lift and 4 buddies helping. It's actually worse alone. One of the worst jobs I ever did and would rather drive it off a cliff than do that again.

Yes, you can remove all the 4x4 components except the transfer case. Hubs were designed to be used without a shaft.

Why do you need to replace the timing cover? Replacing the oil pump?
 
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slidr

Member
Was replacing the front crank seal and marred the seal housing trying to remove the old one.

Screw it, I'm just going to cut a hole in the pan, I'll report back if it actually works.

Thank you.
 

MRRSM

Lifetime VIP Supporter
While I admire your creative idea about Drilling an Access Port in the front, upper Crankcase area to be able to unscrew the Oil Pick Up Tube Flange Bolt... Short of TIG Welding a tiny cover plate over that hole afterwards... you would need to use the most appropriate flavor of JB-Weld to seal up that Port. That being the case... before attempting anything quite so exotic... perhaps you can attack the problem using JB-Weld externally... and use Acetone and Dremel out the Damage (with extreme care not to injure the snout of the Crankshaft) to obtain a better purchase and surface contact area and then fill in the damaged vacancy with shaped JB-Weld and then re-install your Front Timing Cover Seal.

Conversely, you could simply use the Acetone to clean up that same area... and then apply the JB-Weld at the same time you are Cautiously Tapping in the New FC Seal... flush with the Front Cover; leaving it to sit overnight and hope that subsequently... no oil can escape from around the margins of the seal and cover, ensuring that no JB-Weld gets onto the inner PTFE Seal.

Even if you successfully created the Crankcase Access Port... with due consideration that both of the Oil Pick Up Tube fasteners are of the "Trapped" design... there is no guarantee that you would be able to correctly thread that bolt right back up inside of the TC Cover-Gerotor Oil Pump Portion of the Case... and you would risk Smearing the GM ACDelco Special RTV or not being able to get ALL of this work done before it completely prematurely Vulcanizes within the short allotted (10) Minute Cure Time.

So if this huge effort on your part goes sideways... a loss of Oil Pressure might still occur if the Oil Pick Up Tube Sealing Grommet (or the Old Style Blue "O" Ring) does not close the gap enough tight enough and allows a loss of the Vacuum Draw for the Oil Pump to occur. You already know what will follow if that unfortunate event takes place. And so... perhaps the least damaging and the least hasty approach might just be for you to think about using JB-Weld to solve these problems and consider its use as the one course of action to take... causing the least amount of pain for you in the process... :>)

PS...

One last observation... if the "damage" you spoke of is that the Front Cover has cracked enough to allow the Oil Gears Chamber to be compromised... TIG Welding that crack or having to completely replace the Front Cover/Gerotor Oil Pump becomes an absolute necessity. Hopefully this problem is not THAT extreme. The attached images from my Photobucket will help you to visualize the difficulties involved here with access and repair in your suggested approach:

DSC00016.jpegDSC00019.jpegDSC00421.jpegDSC00422.jpegDSC00423.jpegDSC00425.jpegDSC08083.jpegDSC08084.jpegDSC08203.jpegDSC00424.jpegDSC00426.jpeg

"First... Do No Harm...." Hippocrates
 
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Mooseman

Moderator
Was replacing the front crank seal and marred the seal housing trying to remove the old one.
Is that all? I'd just put RTV in the bore and on the seal and drive it in. I'd also smear some on the outside after it's installed. As you said, with its mileage, no need to get all technical about it.

I can't see how punching a hole in the pan can work.
 
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slidr

Member
Is that all? I'd just put RTV in the bore and on the seal and drive it in. I'd also smear some on the outside after it's installed. As you said, with its mileage, no need to get all technical about it.

I can't see how punching a hole in the pan can work.
I wish I would have gone this route, but once I impulsively started unbolting and prying the timing cover, I knew I was screwed because there was no way I would have been able to reseal the cover without pulling it entirely off the car and cleaning the mating surfaces.
 
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slidr

Member
While I admire your creative idea about Drilling an Access Port in the front, upper Crankcase area to be able to unscrew the Oil Pick Up Tube Flange Bolt... Short of TIG Welding a tiny cover plate over that hole afterwards... you would need to use the most appropriate flavor of JB-Weld to seal up that Port. That being the case... before attempting anything quite so exotic... perhaps you can attack the problem using JB-Weld externally... and use Acetone and Dremel out the Damage (with extreme care not to injure the snout of the Crankshaft) to obtain a better purchase and surface contact area and then fill in the damaged vacancy with shaped JB-Weld and then re-install your Front Timing Cover Seal.

Conversely, you could simply use the Acetone to clean up that same area... and then apply the JB-Weld at the same time you are Cautiously Tapping in the New FC Seal... flush with the Front Cover; leaving it to sit overnight and hope that subsequently... no oil can escape from around the margins of the seal and cover, ensuring that no JB-Weld gets onto the inner PTFE Seal.
As I had mentioned to Mooseman, I wish I would have gone the route of fixing the old timing cover instead of going through this mess, but I thought that drilling and tapping a 20mm hole to get access to the pickup tube bolt would be easy, but God I was wrong.

For future reference for anyone considering this route, merely accessing the bolt is only half the battle (all of this is probably abundantly clear to experts such as yourself and Mooseman, but for a lazy dingus such as myself, it was not). Once you have the bolt removed, you have to also pull down the pickup tube about a half an inch or so to uncouple it from the oil pump (at least for the 1st design tube and pump you do). This is impossible because the tube impacts the oil pan, so my 20mm hole turned into a roughly 4x2 inch access panel that I cut out with a dremel and punched out with a cold chisel (this was actually much easier than drilling a hole due to the angle of the oil pan and the frame getting in the way, unscrewing the top of the passenger side motor mount and jacking the engine gave me a few extra inches to work with).

You cannot simply pull the timing cover out and up to try and disconnect the pickup tube that way because the timing cover cannot clear the crankshaft, so movement is limited.

As far as patching up the "access panel" I created, I have large piece of aluminum sheet metal that I was planning on using and for buttoning it up, I was planning on doing the following:

1. Create template and cut the sheet to overlap the edges of the hole by about an inch or so.

2. I was nervous using JB-Weld alone, so I was planning on using several self-drilling sheet metal screws to mechanically fasten the sheet to the pan. I may however forgo this route because if the JB-Weld were to fail, I doubt the entire panel would fall off at once and a leak would slowly develop so I could just watch the ground where I park and keep an eye on it (I don't take road trips in this beast).

3. Where the edges of the hole contacts the sheet, I was going to run a small bead of an anaerobic gasket (which should not create an issue when the gasket seeps into the oil pan once pressure is applied), then adjacent to that all the way to the edge of the sheet I was going to rope a bead of QuikSteel Reinforced Epoxy putty and smooth that out and onto the top of the edges of the sheet. Then once all of that cured, I was going to JB-Weld over it all and taper it out onto the oil pan which should provide a good amount of surface area for the epoxy to bite (I will have cleaned the pan with a wire brush and solvents to promote adhesion).


Even if you successfully created the Crankcase Access Port... with due consideration that both of the Oil Pick Up Tube fasteners are of the "Trapped" design... there is no guarantee that you would be able to correctly thread that bolt right back up inside of the TC Cover-Gerotor Oil Pump Portion of the Case... and you would risk Smearing the GM ACDelco Special RTV or not being able to get ALL of this work done before it completely prematurely Vulcanizes within the short allotted (10) Minute Cure Time.

"First... Do No Harm...." Hippocrates
Can you please elaborate on this? Are you saying that because of the limited room I have accessing the innards of the oil pan with the timing cover on, I may not be able to get the pickup tube to fully mate into the oil pump without re-positioning the timing cover and messing up the seals? If so then that is definitely a possibility I need to look out for, thank you. I'll do some dry runs to make sure I have enough room to manipulate the pickup tube and get it seated. The sealant I plan on using (the timing cover I bought from [Rock Auto] came with Mahle brand aluminum sealant ) states that I need to hand-tighten all of the bolts then wait an hour before torquing them to spec, so do you think this one hour window will allow enough time to get the tube and pump mated?






I also have a few more questions that you guys can probably help me out with:



1. When transferring the oil pump from the old cover to the new one, should I be using any type of assembly lube or Vaseline or grease to pack the space between the inner and outer gears and also lube the outside of the outer gear where it contacts the timing cover (the shop manual only says to use engine oil to coat the parts and makes no reference to priming the pump or using grease or assembly lube)? Or could I prime the pump by pulling the fuel injection fuse and cranking the engine for 5 seconds or so once everything is all buttoned up?

2. While looking at the gerotor gears of the oil pump, I noticed that on the outer gear there was a definite alignment mark (a dot), but there was no type of mark on the inner gear, front or back. I'm an idiot and the marks I had put on the gears and timing cover to note the positioning of the rotors in relation to the timing cover got wiped off while I was handling everything. I can replicate how I believe they should fit together, essentially positioning the gears so the two mating points between both gears exist between the input and output ports (like in the top row, 4th image here)...

Does anyone have a better idea of how they should/could be aligned?






3. I know that the crankshaft sprocket splines on the inner gear and the crankshaft must align, but is this something I can test fit and adjust with the oil pump attached to the timing cover, right? Ideally, I guess I would test fit it before I add the gasket material, and rotate the crank to align as needed, then lock the crank again via the torque converter access hole and 15mm socket trick.

4. Found the quote below in another thread...

Has anyone confirmed whether or not the old oil pump case will work with the new timing cover casting? Looks like the bolded quote below is stating that it's unknown if the new pump will work on the old timing cover, so my situation is the opposite but still applicable. If no one knows then I guess I can be a guinea pig since I am too stubborn to, at this point, drop the pan and replace the pickup tube with the 2nd design.


Courtesy the help from @Mooseman… The arrival of the New OEM GM Timing Cover (Part # 1260934) fitted with the OEM Gerotor Oil Pump (Part # 12576249) allowed me to make a series of side-by-side visual comparisons with the Original GM OEM Timing Cover (Part # 12569166) and the Stock OEM GM Gerotor Oil Pump (Part # 24577543). The significant differences are as follows:

http://s557.photobucket.com/user/60dgrzbelow0/library/0000TRAILBLAZERENGINEREPAIR/TIMINGCOVERGEROTORPUMP?sort=3&page=1

NOTE: AS LONG AS THE OLD STYLE GEROTOR CASE COVER AND GEROTOR PUMP, GEARS AND BYPASS VALVE SHOW NO SIGNS OF DAMAGE OR WEAR AND A BRAND NEW BLUE “0” RING IS USED FOR THE OLD STYLE OIL PICK UP TUBE AS A PAIRED SET… IT WILL PERFORM NOMINALLY AND SHOULD GIVE DURABLE, RELIABLE SERVICE… SO IT IS NOT MANDATORY THAT IT BE REPLACED.

(1) The Timing Cover castings are NOT identical between the Older and Newer Style Timing Covers, The interior areas that handle the nested, directed oil flow cavities opposite where the Gerotor Oil Pump bolts to the inside of the Timing Cover are markedly different. Therefore I cannot swear that the Sealed-Power OEM quality replacement Oil Pump that has the Updated Oil Pick-Up Manifold that matches GM Timing Cover (Part # 1260934) and uses the New Style Oil Pick Up Tube will work or not ...even though the casting bolt holes and support bosses align and allow for it to fastened in place on either Timing Cover.
5. Can I install the crank seal on the cover before mating it to the engine, or should this be done after the timing cover is installed?


Thank you so much, guys!
 
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Mooseman

Moderator
All this is for naught if you can't get the pump off the tube, or did you get it off? Even then, you might not be able to get it back on. What you're doing is sketchy at best. If this doesn't work, you're looking at pulling the oil pan anyway and probably getting a new timing cover with oil pump. And since it would be the new design, you'd need to replace the pickup tube.
 
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slidr

Member
All this is for naught if you can't get the pump off the tube, or did you get it off? Even then, you might not be able to get it back on. What you're doing is sketchy at best. If this doesn't work, you're looking at pulling the oil pan anyway and probably getting a new timing cover with oil pump. And since it would be the new design, you'd need to replace the pickup tube.
Oh, it came off just fine. Hopefully going to install the timing cover and patch the pan tonight, then put the balancer and fan clutch back on tomorrow.

I do have the new timing cover that came with the 2nd design oil pump, but i'm transferring the old pump to the new cover.
 
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slidr

Member
2. While looking at the gerotor gears of the oil pump, I noticed that on the outer gear there was a definite alignment mark (a dot), but there was no type of mark on the inner gear, front or back. I'm an idiot and the marks I had put on the gears and timing cover to note the positioning of the rotors in relation to the timing cover got wiped off while I was handling everything. I can replicate how I believe they should fit together, essentially positioning the gears so the two mating points between both gears exist between the input and output ports (like in the top row, 4th image here)...

Does anyone have a better idea of how they should/could be aligned?

It took a whole 1 minute of playing with the oil pump last night to realize that the alignment of the inner and outer rotors/gears doesn't matter, and that the alignment mark on the driven gear is merely to indicate which side of the gear should be facing which direction (i.e. facing the timing cover or the engine, fore or aft). Derp.
 

MRRSM

Lifetime VIP Supporter
I showed you the images of the engine internals so you could better visualize how close the inlet pipe of the Oil Pick-Up Tube is to the fastener... its not really designed for the Epic Fix you find yourself in right now. Frankly... I was hoping you would overload on all that was involved and at risk from looking over those photos... but I obviously underestimated your determination to "STB". In regards to the position of the Gerotor Gears... your understanding of this is unfortunately ...wrong.

The instructions shown here linked at the bottom of this post will inform you as to the proper position the Gear Set should be in... so that the Sliding Outer Ring can allow for Oil to be Vacuumed into the other gears and 'Achieve the Squeeze' required to push the Oil that is being picked up from the Bottom to get pushed out of the Tube leading into the Engine Block. If you have not committed to finishing the Gerotor Oil Pump installation completely... you owe it to yourself to ensure that the Gerotor Oil Pump will actually work right before you go through all of this trouble and wind up with a 500 Pound Boat Anchor when all is said and done... after you crank it up and the Engine Seizes due to Oil Starvation.

http://photobucket.com/gallery/user/60dgrzbelow0/media/cGF0aDowMDAwVFJBSUxCTEFaRVJFTkdJTkVSRVBBSVIvR0VST1RPUk9JTFBVTVAvRFNDMDM2OTUuanBn/?ref=1

As for using a wide variety of sealants and gaskets to close up the "Battlefield Wound" your Crankcase presently suffers from... you should not use the word "Steel" in any sentence containing the expression, "Aluminum Crankcase Oil-Pan" as they are electrolytically at odds with each other and in all likelihood... they will NOT form a permanent Bond together. J.B. Weld has a multitude of better suited permanent and strong sealants that will work without the necessity of doing any more creative butchery to the Crankcase Shell.

The most important thing is that your work on the re-installation of the Oil Pick Up Tube from the Inside of the Crankcase should include Replacement of the Old Blue "O"-Ring with a Brand New One. If it comes down to "cases", you should use a THIN piece of Aluminum Plate to make up a Patch that is Larger than the Outer Opening in the Oil Pan when slipped sideways into the hole lengthwise and then slide it right back up to mate with the INSIDE of the Damaged area. Before you begin with all of these surfaces... they must all be thoroughly "De-Oiled" of any residues of Gas or Lubrication... inside and out for a considerable margin around that Hole Area using either Lacquer Thinner or Acetone. This next part requires that everything... every surface must be SPANKING CLEAN! (Your Fingers and Hands Included!)

Before you commit to slipping the Patch through that Hole... you must first Drill a few Holes into it and using a piece of Stainless Steel .041" Safety Wire, lace it through...just like a Shoe Lace... then once the Patch is In Place... you can wrap the two wire ends round a small section of Wooden Dowel and then gradually tighten it down from the outside and carefully with the Dowel facing Cross-Wise to the Long Opening braced up against the Outside of The Crankcase... use a pair of Pliers...NOT TOO HARD... to slowly tighten the wires down by rotating them spliced together...and twist them clock-wise until the inner Aluminum Plate begins to press tightly up against the inside of the Crankcase...while The Wooden Dowel braces for the OUTSIDE.

Then all you would need to do is use the Proper Amount of Very Thoroughly Mixed J.B. Weld...again... in a Sufficient Quantity to act as a Plaster over that Large Hole in the Crankcase and basically Spackle the Hell out of it until the outer shape of the J. B. Weld assumes the outer shape and contours of the Outer Crankcase Shell. That Wooden Dowel will have to remain TIGHTLY BOUND for at least 8 Hours afterwards... with no poking and no prodding with your fingers testing at all ...until that "Battlefield Dressing" becomes Rock Hard. Then you simply would have to remove the Wooden Dowel by using Wire End Cutters to GENTLY snip off both S/S Wires at the edges of the J.B. Weld Patch just long enough to bend them over to prevent the Aluminum Inner Plate from falling inside of the Engine if the Patch should Fail. Then... remove the Wooden Dowel and Loose Wires... and take moment to admire your J.B. Weld Repair.

We really want you to extricate yourself from this dreadful problem... but to do so... We need your cooperation by providing as many Detailed Digital Images of your "Work" as possible... so WE can have a better understanding of what you are up against and what might done or suggested so things get better from now on instead of worse. Do this... and help us all out to help YOU!
 

Mektek

Well-Known Member
Gosh, this sounds like a nightmare! Kind of like when I had to use a cutting torch to get a control arm bushing bolt out:explode:
It will be much more difficult to attach the panel from the inside of the pan. I"d attach it from the outside with self tapping screws in addition to the JBweld so that you have a mechanical connection to retain it. The high temperature weakens the epoxy so you shouldn't rely on that alone to hold it on. You can't risk it suddenly letting go while driving.....
 

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