Rear Diff fluid discrepancy between FSM and owner's manual

ANYTHING TO DO WITH MAKING YOUR VAN MOVE EXCEPT FOR THE ENGINE ITSELF.
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Topic author
rlyoung
I am smitten with my van
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Rear Diff fluid discrepancy between FSM and owner's manual

Post by rlyoung »

I have a 2001 AWD van that started our as a rental van and hasn't had any mods. It runs great. The door RPO code shows GU6 for the rear axle. There are no other RPO codes beginning with 'G'. The owners manual says to use 80W-90 Axle Lube in the rear (standard?) differential, but the Factory Manual says 75W-90 SYNTHETIC. The Factory Manual is current to 2/16/01, but the owners manual was printed in 2000. Both differentials had full fluid changes at 32K, but I seen no record of a subsequent full change in any of my service records. I'm at 110K miles. I'm guessing I go with the 75W-90 with no friction modifier, and it wouldn't hurt to change fluid in both diffs? (80W-90 in the front)

Thanks

Captn. Crunch
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Re: Rear Diff fluid discrepancy between FSM and owner's manu

Post by Captn. Crunch »

As you say the only G on the RPO sticker is for the gear ratio, you basically cant go wrong with rear end lube. No G80 means no limited slip so no special additives required. I use the same stuff for both diffs. One less bottle laying about
Captn. Crunch
"I don't beat my rig-I use it to it's maximum potential"
1994 Safari conversion (sold) and miss'n it!
1999 Safari SLE AWD junked
2003 GMC Safari AWD SLT
cast iron Torsen equipped front diff
S-10 leafs-G80 rear w/3.73’s
2” body lift w/Falken Wildpeak AT’s

Topic author
rlyoung
I am smitten with my van
Posts: 34
Joined: Wed May 18, 2016 9:01 am

Re: Rear Diff fluid discrepancy between FSM and owner's manu

Post by rlyoung »

Thanks. I also found this Amsoil site that lists the fluid upgrades that have happened over time for this van, and lot of other specs.

http://www.amsoil.com/MyGarage/VehicleL ... RO%20VAN+W
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