- Dec 29, 2011
- 399
I had some time to change the rear differential fluid in my 2004 Rainier V8 AWD (G80, 3.73 gears) this weekend. It has ~73,500 miles on it. I purchased it used with 50k on the odometer and was told that the fluid was changed at that time as the selling dealer fixed a rear pinion seal. If the fluid was changed, I don't trust a used car dealer to put in good stuff, so I decided to do it myself.
1) I used just around three quarts of Valvoline SynPower (full synthetic) 75W-90 gear lube. On my test drive afterwards, I noticed no noise or chatter from my G80 axle. I expect this fluid to last 75k-100k miles.
2) Could they have put the fill bolt in a worse spot? The housing interferes with wrenches, breaker bars, etc. It's a 1/2" NPT, if you decide to change it.
3) Nine out of ten cover bolts came out easily with my cordless impact. That last one was blocked by whatever that rectangular bar is that goes across the truck (it's not the sway bar).
4) Filling was easy. I attached 12" of vinyl tubing to the end of the bottle and put the other end in the fill hole. There was enough room under there for the bottle.
5) Remove the spare tire. This gives you tons more space in which to work, but it also gives you a chance to inspect your spare. My spare tire was down to about 25psi of air and it was also mounted incorrectly. I've never had it down so this was not a pleasant surprise. According to the owner's manual, mounting the spare tire incorrectly (valve stem down) means the secondary latch system won't work, so if the winch cable breaks, you lose your spare and create a road hazard.
6) Apparently I don't have the 8.625" axle. I thought all V8s did, regardless of wheelbase. I bought a new gasket (Fel-Pro 8.625" gasket at NAPA) but when I compared it to the old one, it was different. The difference is slight, but enough that it will not work. The gasket that was on there, that I reused since it was in very good condition, looked like this (Fel-Pro 8.0" gasket at NAPA).
Does this mean the conventional wisdom that all V8s have the 8.625" axle is wrong? Did I just not do my homework? Is it possible that the original 8.625" axle was swapped out with this 8" one? Any concerns about towing, hauling, or driving with the 8" versus the 8.625"?
1) I used just around three quarts of Valvoline SynPower (full synthetic) 75W-90 gear lube. On my test drive afterwards, I noticed no noise or chatter from my G80 axle. I expect this fluid to last 75k-100k miles.
2) Could they have put the fill bolt in a worse spot? The housing interferes with wrenches, breaker bars, etc. It's a 1/2" NPT, if you decide to change it.
3) Nine out of ten cover bolts came out easily with my cordless impact. That last one was blocked by whatever that rectangular bar is that goes across the truck (it's not the sway bar).
4) Filling was easy. I attached 12" of vinyl tubing to the end of the bottle and put the other end in the fill hole. There was enough room under there for the bottle.
5) Remove the spare tire. This gives you tons more space in which to work, but it also gives you a chance to inspect your spare. My spare tire was down to about 25psi of air and it was also mounted incorrectly. I've never had it down so this was not a pleasant surprise. According to the owner's manual, mounting the spare tire incorrectly (valve stem down) means the secondary latch system won't work, so if the winch cable breaks, you lose your spare and create a road hazard.
6) Apparently I don't have the 8.625" axle. I thought all V8s did, regardless of wheelbase. I bought a new gasket (Fel-Pro 8.625" gasket at NAPA) but when I compared it to the old one, it was different. The difference is slight, but enough that it will not work. The gasket that was on there, that I reused since it was in very good condition, looked like this (Fel-Pro 8.0" gasket at NAPA).
Does this mean the conventional wisdom that all V8s have the 8.625" axle is wrong? Did I just not do my homework? Is it possible that the original 8.625" axle was swapped out with this 8" one? Any concerns about towing, hauling, or driving with the 8" versus the 8.625"?