I just noticed some oil leaking from my differential rear end cover what can i do to fix this problem i have 52000 miles on my truck is this time for new oil and if so which brand and what weight i have stock 3.23 with a g80.

 

Rear end cap, do you mean the cover? If it's the cover gasket, you can replace it with a new factory gasket or RTV, whichever you prefer. I like using the factory gasket, easier to clean if you remove the cover again in the future. As for fluid, the factory G-80 calls for synthetic 75w-90, last time I did mine I got Mobil1 syn gear oil at AutoZone, but again you can really go with whichever manufacturer you prefer.

 

oops yeah i meant cover also how much fluid is needed and is this something that can be done easily? thanks for the advice...

 

Yea it's a piece of cake...get 3 qts of the gear oil and you should have about 1/2 a qt left over when your done IIRC. I'd do a quick run down, but I have to run back to work....

 

stupid easy all ya'll need is a 13mm socket on a 3/8 drive rachet jack up truck put jackstands under it unbolt the cover clean all the old gasket off put new gasket back on bolt cover back on then in the front by the drive shaft is a hex head 3/8 drive will work to get it out put that 3 qts of gear oil in till it runs out the hole and your good to go .of corse put the plug back in

 

Almost any "how to" you will read on here or other forums will tell you to fill the diff until fluid comes out of the fill hole, but this is incorrect. The fluid level should be roughly 1/2" to 1.5" below the fill hole (15-45mm). I measured mine with a paper clip I had bent. If you are going to retain your G80 you will need to use synthetic 75w90 gear oil. My rear took right at 2.18 qt (I'm **** and measured ) and was roughly 1/2" below the fill hole.

 

There is a drain plug on the bottom of the diff. You can remove that and then remove the cover. I like to do this because its less of a mess. Just my .02 cents

 

his truck wont have that plug. Apparently, only selective 99-02s have it.

 

I did not know that. Thanks for pointing that out.

 

Yep, apparently it was a cost cutting measure by GM