I've been searching for hours and haven't come up with a decent answer.

True-trac recommends conventional (non-synthetic) gear oil. I'm not sure a 75W140 non-synthetic gear oil is made so what is everyone running?

My install is gonna be on the first and I'm sure I'll have to order the oil, instead of picking it up at a store. I know there are several people running the True-trac, I need some insight.

 

90-120 synthetic in mine

 

Any noise or lack of operation from running synthetic?

 

I run 85W140 non-synthetic from Valvoline that I ordered on-line. My local Tractor Supply also stocks non-synthetic 85W140 under their Traveller brand.

The small weight change from stock has not caused any issues in 50K + miles of use including a few winter trips to northern Quebec.

 

The VV825?



That's one I've been looking at, only thing that concerns me is the friction modifier that's already in the oil.

Other one I'm considering is the Lucas 85W-140 Heavy Duty but can't seem to find if it's synthetic even though I've read it's conventional.

 

Yes, Valvoline High Performance Gear Oil 85W140.

The additive has not caused me any issues. The guidance I have seen says you do not need LSD additive but I have not see anything that said to avoid it. They do recommend against synthetic.

This link has some related FAQs for the Truetrac from the manufacturer about 3/4 of the way down the page:

FAQ

 

Mine is semi synthetic lube, no noise.

 

I used lucas in mine, and it has now been a few years, and one northern winter, and no issues to speak of. It was the Lucas heavy duty synthetic type.