99 Sierra 1500 both diffs and transfer case fluid recommendations ??

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Jan 25, 2014
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south haven mi
i want to change out all the fluids the trans is the auto pushbutton what fluid can i run is maxlife ok or do i need the GM fluid?Also i am doing both diffs and going to use GL5 supertech or mag1 full syn 75w/90 is this the best option and the eaton lockers do not require any additive correct? Has 240k also front is listed as 1.75 qts rear 2.5 what is transfer case capacity?
 
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I used the Supertech synthetic gear oil in my 2017 Silverado differentials. I don’t recall the transfer case, googled it up, checked the manual.
 
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Here is the fluids page from your owners manual, the fluid recommended for the transfer case in 1999, and the fluid it was replaced with. Currently the fluid reccomended for the transfer case is Auto Trac II, which is readily available at Auto part stores, or if you can’t find it, at your GM dealer. There is no mention of a need for a limited slip additive in the rear end. :)

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rear and front diff - mobile 1 75w90 - my owners manual does not mention limited slip addy

Transfer case - mine specs out Dex VI,
I use amsoil's website to look at fluid specified

Yours must be a manual transfer case. The OP has an automatic transfer case with a auto push button control.
 
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just food for thought, I have used AT2 in my trailblazer for a full index. Worked fine. Now running a thick 7.7cst group 4 based multi vehicle ATF. After 2 years in use, the auto trak still runs like a top.

Every transfer case I have serviced, which is not many, my trailblazer, ram 1500 and my 3500 all took around the 2 litre mark.
 

cknight49090

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Jan 25, 2014
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south haven mi
i am going to use super tech mag 1 or wolfs head all around 8.00 for full syn it takes 5 qts for both diffs.And 2 qts of the valvoline transfer case fluid which is spec'd for the clutch style transfer case or auto type.The valvoline is 8-9 a qt it takes two thanks.
 
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