Chevy and GMC Duramax Diesel Forum - View Single Post - What oil should I use in ZF 6-speed and rearend?

**ob_1jr** · 05-28-2007, 02:58 AM

Well, from my owner's manual, it states:

Manual transmission (6 speed) - TranSynd™ Synthetic Transmission
Fluid (GM Part No. U.S. 12378515, in Canada 88900701).

As far as the rear end: SAE 75W-90 Synthetic Axle Lubricant (GM Part No. U.S. 12378261, in Canada 10953455)meeting GM Specification 9986115.

I think the rear end fluid this lists is for the "grape Juice" and it is very expensive (like $25 or more a quart...rear end takes about 4). I have been running mobil 1 synthetic gear lube. as long as it meets the GL5 rating, you are good to go. No friction modifier needed either.

PM me your e-mail address and I can send you an electronic copy of the 3 manuals that came with mine.

05-28-2007, 02:58 AM	eBay Motors #2 (permalink)
ob_1jr Super Moderator Join Date: Aug 2005 Location: Alaska Posts: 1,818	Well, from my owner's manual, it states: Manual transmission (6 speed) - TranSynd™ Synthetic Transmission Fluid (GM Part No. U.S. 12378515, in Canada 88900701). As far as the rear end: SAE 75W-90 Synthetic Axle Lubricant (GM Part No. U.S. 12378261, in Canada 10953455)meeting GM Specification 9986115. I think the rear end fluid this lists is for the "grape Juice" and it is very expensive (like $25 or more a quart...rear end takes about 4). I have been running mobil 1 synthetic gear lube. as long as it meets the GL5 rating, you are good to go. No friction modifier needed either. PM me your e-mail address and I can send you an electronic copy of the 3 manuals that came with mine. __________________ 2004 GMC 2500HD D/A CC Carbon Metallic w/ LB7 4" turbo back MBRP exhaust TST Powermax Programmer, Diablosport Predator 285/75-16 BFG T/A KOs, Eagle Alloys Series 187 Clifford 2 way remote start, High Idle, Bilsteins Extang Classic Platinum Tonneau Cover AFE Magnum Force Stage 2 Proguard 7 intake Kennedy Diesel Merchant Automotive My Photos