I've just received my new truetracs and yukon gears and am getting ready to install in a couple of days. Been reading the threads on gear oils trying to decide what to use. I plan on using only petroleum base and have read good reviews on amazon for Torco 85W-140 Racing*gear oil. Does anyone have any experience with this oil? I know dynatrac recommends it. If not, what is a good petroleum oil for diffs?

 

I use the Lucas gear oil with my front and rear truetracs. Good quality and not expensive.

 

Any particular reason for running the 85-140 weight ?

 

I'm guessing he tows. The manual recommends 75-140 for towing. If not towing, then 80-90.

FWIW, I only use Torco oils in my Harleys.

 

Yeah, that's kinda what I figured , I used to run Torco 50w in my old 76 FL ( shovel ) good oil..

 

Yes, I sometimes pull a trailer. Also figure off-roading puts the same pressures on diff as pulling a trailer. Still trying to decide what to use with truetracs. I was reading the paperwork that came with the truetracs and It says it's ok to use synthetic oil. Just needs to meet GL-5 standard. So I'm still reading up on oils and looking for suggestions. It's my understanding that I need an oil without the friction modifier additive. I'm probably over thinking all of this. I'll probably just go to local parts store and pick up whatever they stock.

 

The owners manual recommends synthetic in the rear for towing applications. That's for stock parts. My understanding of friction modifier is that if you don't have limited slip then it doesn't matter whether or not the modifier is in there. Most synthetics already have the modifier. No harm no foul if you use that even without limited slip.