Hello Guys

I got a 2002 GMC Yukon XL 2500 series (8 lug)
and not sure what diff oil to use and how much of it I need to buy.

Rearend I believe is a 14 bolt
no idea or sure whats on the front

Was planning on running Royal Purple
75w90 front
75w140 rear

How many quarts, pints or containers of the stuff do I need to do the job and do I need to add any
limited slip additives for either front, rear or both diffs.

thanks

 

Royal Purple or Redline is the stuff of choice. Friction modifier in the rear differential if not one of those two (they are pretty slick already).

Rear axle: SAE 75W-90 Synthetic Axle Lubricant
Front axle: SAE 75W-90 Synthetic Axle Lubricant

DIFFERENTIAL FLUID CAPACITY
Front Axle 1.73 Liters (1.83 Quarts)
Rear Axle 2.6 Liters (2.75 Quarts)

 

Use A GT5 synthetic 75-90 gear oil and will already have the friction modifier in it.

 

Amsoil did a test of a bunch of gear oils and royal purple did **** poor in it, in the end it ranked 3rd.. The 3rd worse gear oil in front of Lucas and mopar synthetic. Mobil 1 synthetic was right up with amsoil followed by GM synthetic gear oil. For the best bang for your buck I'd go with Mobil one, also if you have a g80 in the rear diff you shouldn't need any extra limited slip other than the pre added amount. GM and Eaton both say you shouldn't use limited slip additives with g80s