Differantial oil

[acres90]

Im going to change the oil in my front and rear diff on my '13 denali AWD. I think im going to use 75/90 synthetic...do i need a limited slip addative?

 

[swathdiver]

Im going to change the oil in my front and rear diff on my '13 denali AWD. I think im going to use 75/90 synthetic...do i need a limited slip addative?

No additive.

 

[Foggy]

Nope.. The rear G80 does fine with GL5 spec gear oil

 

[Fless]

Does the front diff take a different weight oil on these? It does on my NBS.

 

[George B]

Does the front diff take a different weight oil on these? It does on my NBS.

Yes, 80w90 in the front and 75w90 rear.

 

[OR VietVet]

Welcome to the forum and you have the correct answers. Were you going to use the same fluid for both before @George B set you straight?

 

[Onlyone]

I run Amsoil 75w90 in mine, front and back. It won’t make a bit of difference. Make it easy on yourself. Owners manual confirms for my Denali

 

[swathdiver]

Correct, GM has changed the recommendation for the front differential from conventional 80W90 to full synthetic 75W90. This applies to our older trucks as well. Never understood the reasoning for two different fluids, maybe the older spec was quieter?

Limited slip lube in a stock truck G80 causes chattering.

 

[Fless]

Correct, GM has changed the recommendation for the front differential from conventional 80W90 to full synthetic 75W90. This applies to our older trucks as well. Never understood the reasoning for two different fluids, maybe the older spec was quieter?

Limited slip lube in a stock truck G80 causes chattering.

Would you be able to point to written documentation of said change of recommendation?

 

[acres90]

Thank yall for the input. I changed diff oil in my '99 corvette and it said to use limited slip additive, reason I asked. Thanks!

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

You are already receiving sage advice from the knowledgeable folks on this Forum.

 

[Doubeleive]

boy that weatherstripping pfpe lube is expensive, a little itty bitty 1oz bottle is over $50
I figured mine is 10 years old and I have never lubed the weather stripping as recommended, but I do clean them with 409
shopped around and this looks like the best price $36 for a 2oz so I got some, should last a while apparently a tiny bit goes along way
https://www.ebay.com/itm/1753755914...lRdkzI68D1W4ikn78iJYCMjmmep2|tkp:BFBMxO2749Fh

 

[BlaineBug]

boy that weatherstripping pfpe lube is expensive, a little itty bitty 1oz bottle is over $50
I figured mine is 10 years old and I have never lubed the weather stripping as recommended, but I do clean them with 409
shopped around and this looks like the best price $36 for a 2oz so I got some, should last a while apparently a tiny bit goes along way
https://www.ebay.com/itm/175375591491?hash=item28d5332843:g:j-MAAOSwqLVi87FQ&amdata=enc:AQAHAAAA4Na1H/v36GS8azafkM0c5NSIr/lv/g8yqqe1dxSK4xWwkcs3E3jAKnEq6nDDFrIfs3NpjKs76Dvlszz+yqRmj4ZTqu12IQiB7VnLDGscvHyb955GC/8O175php13JUTzu/ldOpygDqoucgHZ343+QQqqneqZ2dfHuT+p41LW0lfYCK4drZ8J4sbysJuKKVQFiOXGiScAYmAlJ0Fd2wB014J0BZ6PkbzU52YMAO9KLAsyQGddvhDsN+UphT0sAidm4nccZtlD6JzxAHXplRdkzI68D1W4ikn78iJYCMjmmep2|tkp:BFBMxO2749Fh

Silicone spray should also work good, no?

 

[BlaineBug]

My 2019 Yukon's owners manual calls for 75W-90 in the front and 75W-85 in the rear. Can you use either of these weights in both the front and the rear? Probably!

 

[acres90]

Hiw much do they hold?

 

[Doubeleive]

Silicone spray should also work good, no?

probably but the stuff they say to use is pfpe type because I guess it soaks into the rubber and it's not affected by heat or cold, the stuff I linked is used by volkswagon, land rover, gm. I don't know not an expert by any means but $40 didn't hurt too bad for something I need to do anyway. I already replaced the inner door seals and those were not cheap so I guess it couldn't hurt to lube them all and maybe have them last a little longer

 

[BlaineBug]

Hiw much do they hold?

Transfer case: 1.6 quarts

Differentials are about 2 quarts each, not listed in the manual. Fill until full and seeping from fill plug opening just like the transfer case.

 

[acres90]

Just got done with the front...held right at 2 qts

 

[acres90]

Transfer case: 1.6 quarts

Differentials are about 2 quarts each, not listed in the manual. Fill until full and seeping from fill plug opening just like the transfer case.

Is gasket on the rear reusable?

 

[gooffeyguy]

Yup, my 2012 owners manual shows 75w90 synthetic for both