Synthetic warning sticker above rear fill

[TonyD]

On my 2000 GMC Sierra 1500 that I bought there is a sticker above the rear diff fill hole that basically says synthetic gear oil takes less than dino. Does that mean the dealer installed synthetic and put that sticker there? Or is it on all vehicles? I bought three quarts of Mobil 1 and GM additive to change over. Just checking to see what the sticker means..

[RyanbabZ71]

The 99+ trucks take synthetic fluid in the rear ends. Mobil 1 is synthetic. Also you do not need the additive that is only for the pre 99 trucks

[TonyD]

Thanks! I knew that at one point and forgot..It is the front that is not synthetic..Can I use the Mobil 1 for the front? I bought 3 quarts. How much does the front take? thanks again.

[RyanbabZ71]

I have been reading you can put synthetic n the front. It requires 80W-90 however many people have been saying there is a TSB to use 75W-90 synthtic if you live in cold climate.

 

Here are the fluid capacities per the helms manual

 

Axle

Rear 8.6 Ring Gear 2.0 Liters 2.1 Quarts

Front 1.66 Liters 3.5 Pints