Rear Diff Oil Change

NothinButBowTies · May 29, 2004

Hey Guys,

Went to change the fuel filer today and the rear end fluid. The filter was a piece of cake, but when I went to drain the gear oil, (G80) I couldnt find the drain plug! Can someone help me out here? The only thing I was thinking was that on the 2003 you have to pull the pumpkin cover off to drain?

Also, what tool do you use to open the fill plug?

Thanks, Nick

tmf6902 · May 29, 2004

check out the guides section on the left hand side of the site. There are instuctions and pics there.

Taaaaaaahoe? · May 29, 2004

check on the bottom of the actual diff, not the cover..

Mike

snoman · May 30, 2004

Hey Guys,
Went to change the fuel filer today and the rear end fluid. The filter was a piece of cake, but when I went to drain the gear oil, (G80) I couldnt find the drain plug! Can someone help me out here? The only thing I was thinking was that on the 2003 you have to pull the pumpkin cover off to drain?

Also, what tool do you use to open the fill plug?

Thanks, Nick

Most rear axles do not have drain plugs. Just lossen cover and let oil drain out the retighten cover bolts and fill unit.

Taaaaaaahoe? · May 30, 2004

my Tahoe has a drain plug

snoman · May 30, 2004

my Tahoe has a drain plug

Consider yourself lucky as my 2000 K3500 with bulletproof corp 14 bolt 10.5 ring gear axle does not. Personally, it is not a big issue to me anyway.

bigdogs · May 31, 2004

Nope the 10.5" units didn't have them (had to drain the one I put on my Blazer a few times). The newer 11.5" that are on the 2500HD and 3500's have them I believe (need to crawl under mine to double check tho).

snoman · May 31, 2004

11.5 inch ring gear in a rear end. Now even less ground clearance in standard equipment. I heard than the new 11.5 is cheaper to make because it does not have a straddle mount pinion in a removable pinion carrier like the old 10.5 does. There is a new 10.5 also out that does not have a straddle mount pinion either of the old 14 bolt corp.

bigdogs · May 31, 2004

The ground clearance loss (if any) is not really an issue for me. True it does not have the removable pinion that the older 10.5" units had (that was what I put in my Blazer along with a Dana 60 in the front) but has a higher load capacity than the the 10.5" models. It is rated for 11000lbs GAW and 8330 lbft of torque....So not real concerned anything twisting in there... The new factory lockers also work a LOT better than they used to in the old 10.5" models. After dealing with it's "odd engagement" in the 10.5, out it came and in went a Detroit Locker, along with a PowerLok in the front.

snoman · May 31, 2004

The ground clearance loss (if any) is not really an issue for me. True it does not have the removable pinion that the older 10.5" units had (that was what I put in my Blazer along with a Dana 60 in the front) but has a higher load capacity than the the 10.5" models. It is rated for 11000lbs GAW and 8330 lbft of torque....So not real concerned anything twisting in there... The new factory lockers also work a LOT better than they used to in the old 10.5" models. After dealing with it's "odd engagement" in the 10.5, out it came and in went a Detroit Locker, along with a PowerLok in the front.

I never cared for the "gov loc" that GM uses. IF they changed they just did recently. The gov loc in the 10.5 was pretty durable though if you could live with its operation quirks. GM should have long used the Eaton LSD instead. They could have beefed up the tubes on the 14 bolt to carry more weight like Dana does on the 70 but 11.5" looks better in the numbers game too.

bigdogs · June 1, 2004

I hated how that old gov-lok worked I'd get that Blazer sideways quite often with it as you never knew when it would lock up. This newer one (also built by Eaton) is much more dependable and better behaved. Having the discs on the back is also nicer than those planter sized drums on the old one. What I wish is that GM offered a posi for the front end on these IFS units.