Front Diff Re-seal / Replacment

RivMan

Original poster
Member
Dec 4, 2012
8
Hey guys, first post here.

About 8 months ago my Wife's 03 Bravada started making a grinding sound in the front diff. The diff leaked all of the fluid out from the case half seal. I didn't have much time to mess with it, so I just pulled the front Driveshaft and both CV shafts. Problem "solved" and no more noises.

I recently picked up a used Diff, same gear ratio, that seems to be in great shape for it. I want to split the case, check for any damage, and replace any seals that could leak, and re-seal it properly.

Any tips, tricks, ect. I don't want to have to mess with the "Black Magic" of setting up a new diff properly, so if splitting the cases is going to cause an issue there, I'll skip that!

Am i correct in assuming that I just have the 2 output seals along with the pinion seal? Should I just use RTV to seal the case halves together?

Thanks
-Rob
 

BRomanJr

Member
Dec 9, 2011
371
RivMan said:
Hey guys, first post here.

About 8 months ago my Wife's 03 Bravada started making a grinding sound in the front diff. The diff leaked all of the fluid out from the case half seal. I didn't have much time to mess with it, so I just pulled the front Driveshaft and both CV shafts. Problem "solved" and no more noises.

I recently picked up a used Diff, same gear ratio, that seems to be in great shape for it. I want to split the case, check for any damage, and replace any seals that could leak, and re-seal it properly.

Any tips, tricks, ect. I don't want to have to mess with the "Black Magic" of setting up a new diff properly, so if splitting the cases is going to cause an issue there, I'll skip that!

Am i correct in assuming that I just have the 2 output seals along with the pinion seal? Should I just use RTV to seal the case halves together?

Thanks
-Rob

Inspect the case split for signs of leakage first. Once you remove the fill and drain plugs, drain the fluid and see its condition, that should tell most of the story. If there are only slight glimmers of metal in the oil, IMO all is well.

Once the oil is out you can partially inspect the internals using the fill and drain holes with a light. Then check if the pinion bearings seem tight and gear lash is minimal.

You will know if there is damage, pull the original and inspect/compare, probably find a bit of damage.

IMO splitting that case is only if you find a problem (leak) and need to fix. Of course if you see a major problem with the replacement diff you'll want to take it back.

There was also a TSB concerning case halves leaking near the pinion that involved removing some diff mount bolts, inserting shims between diff and oil pan near the pinion, then putting bolts back in. You should make sure you are aware of this in case your current diff has been shimmed and they fall out when removing it. Not sure if the TSB addressed poor machining of the diff, or the oil pan, or both.
 

Mooseman

Moderator
Dec 4, 2011
25,507
Ottawa, ON
Did you also get the disconnect on the passenger side? It too could be the cause of the problem. Add some fresh grease in it.
 

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