Found my oil leak

Stryker11

Original poster
Member
May 20, 2016
152
North Texas
Looked like I had an oil leak coming from the backside of the front axle disconnect. I was hoping it was something stupid but unfortunately it was not. It appears that maybe a previous repair was to blame as it looks like an apparent drill mark in the pan? Either way, it's a cracked oil pan and I've got to deal with it. FML.
 

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m.mcmillen

Member
Apr 29, 2016
554
Wisconsin
Part of me says that I would clean that crack up really good and fill it with JB weld. The other part of me says that the pan is structural and might crack more with all the stress it gets from the 4WD.
Decisions decisions....
 
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Mooseman

Moderator
Dec 4, 2011
25,260
Ottawa, ON
Maybe JB Weld could patch it?

Edit: @m.mcmillen beat me to it. Good point about the structural part.
 
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mrrsm

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Oct 22, 2015
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If necessary for this issue, there are plenty of replacement Crankcase - Oil-Pans available to choose from on eBay:


Here are some close up Images of a thoroughly cleaned up Crankcase Oil Pan to compare against the present position of the crack showing on yours in relation to what the INSIDE structures look like. It is recommended that you "Stop Drill" the Crack before it propagates any further.

Please... Pay Special Attention to the Two Hidden Bolts found under Two Rubber Plugs in the area between the Transmission Bell Housing and the Engine Block. If you forget to remove them and Flex or Bend the Pan up and Down... you can easily Crack and Break Off that Rear Bolt Flange.

GM42LOILPAN1.jpgGM42LOILPAN2.jpgGM42LOILPAN3.jpgGM42LOILPAN4.jpgGM42LOILPAN5.jpg


Note also, as offered by @Mooseman 's original information years ago, these Highlighted Threaded Bolt Holes located on the Outer Flange areas of the Oil Pan are necessary for using Two of the Small Crankcase Bolts screwed therein very slowly and evenly on BOTH Sides in order to Separate the ACDelco OEM Hardened Silicone Crankcase Sealant from in between the Oil Pan and the Engine Block. No other Method will work:

GM42LOILPAN9.jpgGM42LOILPAN8.jpgGM42LOILPAN7.jpgGM42LOILPAN6.jpg
 

Stryker11

Original poster
Member
May 20, 2016
152
North Texas
I agree, I'm leaning toward the JB weld repair. A buddy of mine suggested the Magnum 44 steel putty to use for the repair to maybe help reinforce the oil pan. I'll look into that as well..
 

Uncleenvoy

Member
Feb 12, 2020
545
Ny
I just discovered this after doing an oil change and looking under the truck just to find all that lovely mobil1 5w30 pouring out on to the driveway..crazy part is I've been taking pictures and posting in another forum about a front disconnect job I'm struggling with and never noticed the hole
 

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Stryker11

Original poster
Member
May 20, 2016
152
North Texas
Oh damm, that's crazy. I wonder what caused the hole. Did your disconnect assy come out in one piece or did you have to drill it? Did you have a leak for a while?
 

mrrsm

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Oct 22, 2015
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Jesus Wept...

Given the position and shape of that Hole...Is there any chance that you used a Pry Bar in order to leverage the Transfer Case off of its Crankcase Side Mounts to break the electrolytic corrosion seize-up in between the CV Axle Coupler?

(1) As bad as this sounds... I actually hope that this is the case ... because this problem CAN be FIXED as long as you can use enough Spray Brake-Kleen Inside and Out to dissolve ALL of the Oil Residue inside and out and get down to Bare Aluminum.

(2) Then .. you WILL be able to Sandwich Two Slender Pieces of Plastic positioned with one INSIDE and the other OUTSIDE and Threaded together using a Length of some 0.041" Stainless Steel Safety Wire with a Big Glob of High Temp JB-Weld to act as the "Peanut Butter" in between.

(3) With the Safety Wire holding the two Plastic halves gently together like a Shoelace ...after allowing the Reapir to cure for 4-8 Hours... it should be able to HARDEN AND HOLD FAST. Afterwards, you would just need to carefully snip off the remaining Braided Safety Wire and the JB-Weld-to-Aluminum 'Sandwich' should become a Permanent Fix.

Please forgive my poor exaggerated "Hand Drawn CAD Image" showing this concept..This is a VERY Do-Able FIX.. :

JBWELDPATCH.jpeg
 
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Uncleenvoy

Member
Feb 12, 2020
545
Ny
Oh damm, that's crazy. I wonder what caused the hole. Did your disconnect assy come out in one piece or did you have to drill it? Did you have a leak for a while?

Disconnect came out in pieces it was a real pita...looking back at pics I have I think I know what happened..I used a screw and nut to press the disco off against the oil pan and i neglected to put some thing between the screw and the oil pan so yeah..don't do that. Here's the link to the thread
 

Uncleenvoy

Member
Feb 12, 2020
545
Ny
Then once the main part of the disc was out all the chiseling hammering and drilling probably just pushed it to the limit
 

Uncleenvoy

Member
Feb 12, 2020
545
Ny
@MRRSM I didn't use a pry bar..used nut and screw and didn't put something between the oilpan and screw to spread the force..the fix u suggested. It's with the oil pan removed yes?
 

mrrsm

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Oct 22, 2015
7,641
Tampa Bay Area
Understood... and your honest answer sidesteps any concerns I had about something in the Rotating Assembly going sideways and causing this damage from the Inside. Naturally, if the Crankcase-Oil-Pan is completely removed, the BEST Repair would be to have the Crack TIG Welded to achieve the most permanent results.

However, the Fix should work just as well if the Repair is done WITH the Oil Pan still installed. The Pan must first be Drained and the Oil Filter Removed to ensure that no residual Oil can invade the work area during the repair. Remember to STOP DRILL all of the Sharp, Mating Angles of the Hole edges and near the perimeter around the Crack(s) to prevent their further propagation.

If the metal surfaces are properly prepared and immaculately cleaned with Brake-Kleen Spray Solvent, well mixed binary components of the High Temperature JB-Weld can work to resist Chemicals, Oils and Engine Vibrations and the breakdown of the adhesion of that stuff at operating temperatures up to 500 Degrees Fahrenheit. The position of the Bolt-On Oil Pan should be well below the reach of the rotating Crankshaft Counterweights and Connecting Rod motions, so the risk of them making any direct contact with the Fresh JB-Weld after the Repair is finished and it hardens is very low.
 
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