My front differential is leaking, appears to be coming right between the dif and cover. Is that common? Anything else I should check before replacing the gasket?

Btw I drained and replaced both front and rear with mobil 1 75W-90 synthetic gear oil. Both front and rear leaked from the drain plug before, fixed that. Rear no longer leaks, front does from what appears to be between housing and cover.

 

Clean it off and confirm the leak point. I would say a diff gasket leak is not common.

 

Check the cover bolts. Are they all torqued to spec?

 

That's what I read, what are the common leak points? I thought I was leaking from the drain plug before, put a new washer in and some Teflon tape on the threads. Wiped, cleaned, and confirmed it's not the drain plug. Appears to be coming from between the cover and gasket, could be trickling down from somewhere.

Will check, thanks Doc

 

Finally found some time to crawl under. Front differential cover bolts were all torqued to spec. Started to remove the bolts to replace the gasket, they weren't just torqued to spec but rather over torqued and someone put what appears to be lock tight or something on the threads (was all covered in white crusty stuff). End up breaking one of the bolts I gave up for the day. Are these cover bolts supposed to be this tight?

Either way, now I need to take all the bolts out and replace them, extract one, clean the threads etc. What I thought was going to be a one day job looks like its gonna take some time. Any tips on removing the cover?

I do need to replace rack bushing also, maybe moving that out of the way will help with extracting the broken bolt.

 

H3 diff cover bolts spec is 18-20 ft. lbs.

I went to 20 ft. lbs. on my old 07 with one of our covers on the rear. With lock washers, never an issue.

 

That's what I thought, someone must have over tightened them and used lock tight. The bolt that snapped is just above and left of the fill plug. There literally no room for a drill.

 

What is the proper size bolt anyway? Is it supposed to be 5/16 - 18 inch or M8 x 1.25? Because who ever serviced this dif previously put metric in, probably why they were so tight. Needless to say I am screwed, bolt extractor broke, so now I have a bolt and extractor suck in there might have to remove the entire dif at this point and take it somewhere.

Or can I get away with just 9 bolts instead of 10? The one that broke off is above the fill line, so I am not sure how critical it would be. I feel pretty defeated at this point.

 

Every fastener on the H3 is metric. Diff cover bolts = 8MMx1.25. The prior owner or a service tech just went dumbchit Gorilla mode and overtightened. The OEM bolts came with a thread locker on them, they just need to hold that thin cover in place to form a seal, there is no stress on the bolts.

Older GM Diffs had SAE.

Can you fit a short bit on a 90 degree drill in the space to drill the bolt for an extractor? I have a Dewalt 20V 90 degree drill with deep chuck, it can get in some fairly tight quarters.

 

weld a nut onto it like the exhaust manifold bolt issue.