Recommended Fluids - Transfer Case, Front Diff, Rear Diff

[Meccanoble]

This site has blessed me with the knowledge to change all the fluids in my truck when i first got it. I wanted to see if the recommended fluids changed along with how much. I tried searching but I only seem to find discussions of issues/replacements rather than maintenance so far. I believe I have the G80 Rear Diff

VIN # 1GNSKBE03BR362322

I believe Transfer case takes Auto Tranny fluid (synthetic)
Front/Rear Diff takes 75w-90?

Thanks in advance

 

[Foggy]

You got it... Transfer case Dex VI spec...
Front and rear diffs: 75-90 synthetic gear lube
Get Er Done

 

[Meccanoble]

You got it... Transfer case Dex VI spec...
Front and rear diffs: 75-90 synthetic gear lube
Get Er Done

THanks. Any brands you recommend and how much? My understanding is most Dex VI were created equal so dont matter there but that gear oil....

 

[OR VietVet]

If your RPO sticker, on the inside of the glove box cover, says G80, then it is a G80. If you have an owners manual, that is where I like to get all the fluid specs at. I like to use Genuine GM fluids at all times.

 

[Foggy]

You will be fine with whatever brand is easiest for you to find...
I like the valvoline, etc ... But as long as it's synthetic GL-5 you will be just fine

 

[Bob2C]

I used AMSOIL severe gear 75w-90 for the diffs and ATF Signature for the transfer case. Should last an easy 100k.

 

[Meccanoble]

I used AMSOIL severe gear 75w-90 for the diffs and ATF Signature for the transfer case. Should last an easy 100k.

I think the DIFFS can go 100k miles but i hear the transfer case has to be changed every 30-50k miles?

 

[Meccanoble]

Going with Felpro gasket and permatex black gasket maker combo. Confirmed 10 bolt diff. Using 3 qts of valvoline 75w 90 for rear diff, 2 quarts for front diff, 2 quarts of tranny fluid for transfer case. Blue loctite for rear diff bolts and white loctite for fill and drain plugs. Saving this for future repairs. Currently @ about 235k miles

 

[donjetman]

Going with Felpro gasket and permatex black gasket maker combo.

You might want to use Permatex 81182 gear oil rtv: https://www.amazon.com/Permatex-81182-Gear-Gasket-Maker/dp/B0023GM2KK?th=1

 

[Just Fishing]

You will probably find like me, the rear axle has the molded rubber/steel gasket.
Those are reusable.

Just don't over tighten the bolts.

 

[Bob2C]

Something I just found out. The service manual actually calls for using new bolts when installing cover. Hmmm. I reused my old ones. Oh well. Torque is 30 lb ft.

 

[Geotrash]

Something I just found out. The service manual actually calls for using new bolts when installing cover. Hmmm. I reused my old ones. Oh well. Torque is 30 lb ft.

Yep, you won't have any problems. They probably do it to ensure the bolts can be torqued as close to the spec as possible. Old bolts with rust and crud on the threads will have a wide variance in clamping force for a given torque.

 

[FasterBass]

Why oh why isnt there a drain plug on these diffs?! Coming from IRS rears, I have never seen one without a drain plug.

 

[Geotrash]

Why oh why isnt there a drain plug on these diffs?! Coming from IRS rears, I have never seen one without a drain plug.

My Land Rover LR2 has IRS and lacks a drain plug as well.

 

[FasterBass]

My Land Rover LR2 has IRS and lacks a drain plug as well.

LAND ROVER there's the problem. JK. Had a 98 Disco, nearly indestructible as long as the head gaskets didnt fail.

 

[Geotrash]

LAND ROVER there's the problem. JK. Had a 98 Disco, nearly indestructible as long as the head gaskets didnt fail.

Ah, a fellow connoisseur. I had an '04 Disco II and a '07 LR3 as well. Of those two, the Disco II was the better truck in terms of reliability. Same Buick-derived V8 as yours, but in 4.6L form. Lots of folks had head gasket and oil pump problems with their 4.6's but I got lucky and never had a lick of trouble with the truck.

The LR3 needed both engine and transmission work in the first 50K (serious oil and fluid leaks) - all out of warranty by a few months, of course. The engine was leaking at the bed pan gasket, which was the result of a factory defect, according to the dealer. But the engine had to come out to repair it. $7K later and I traded it in on a new BMW, which was flawless thankfully.

The LR2 has been great, with 230K on it now. Well, apart from needing a new rear differential pinion bearing every 100K anyway :-D

 

[swathdiver]

That's funny to me as the cover isn't under any stress or movement. They want you to inspect the internals is probably why there is no drain plug. The original gaskets are re-useable.

 

[donjetman]

Every couple of yrs I suck as much as I can out of the fill hole and replenish w/Amsoil 75w90.

 

[Meccanoble]

Going with Felpro gasket and permatex black gasket maker combo. Confirmed 10 bolt diff. Using 3 qts of valvoline 75w 90 for rear diff, 2 quarts for front diff, 2 quarts of tranny fluid for transfer case. Blue loctite for rear diff bolts and white loctite for fill and drain plugs. Saving this for future repairs. Currently @ about 235k miles

Months later, 241k miles and no leaks/issues.