RAMAIR57

I know synthetic is not recommended with the Eaton, but do I want to use synthetic or regular rear fluid with the Detroit TrueTrac?? Which fluid is best in this case, and do I use the additive like with the Eaton??

SS SLP2

iTrader: (8)

I think the "TrueTrac" use clutchs, in which case,
" regular" with additive
my .02's, Johnny

BillS

iTrader: (13)

No there are no clutches in the tru-track, it is a helical gear posi, so synthetic is fine. it is just a stronger version of the torsen posi.

RAMAIR57

so synthetic is "fine", but which is preferred? Also, additive or no additive

NOBR8KSS

iTrader: (12)

The preferred fluid should be noted with the instructions that came with the TruTrac.
You do not need to use the additive for a helical posi.

I prefer the Mobil 1 75W-90 with no additive in my Torsen rear-end. It quieted the whirring noise I was getting.

pla-tym

Moser recommends petroleum base gear oil (not synthetic). I just installed a Moser 12 Bolt w/ a tru-trac. I prefer to use Mobil 1. I wonder why Moser says no.

ChevyGoldfinger

I also wonder why Moser says not to use anything but Dino oil. I have one of their 9" rearends with a Detroit Locker, and have gone along with the "No Synthetic"
rule, but have read some really good things about the gear oil made by Amsoil, Redline, and others. It seems they have come a long way in engineering the shock loads on big gears, and of course they lube better while keeping things cooler. If I had the nerve to try it, and was sure it would work without somehow damaging things, I would be all over the synthetic heavy duty oil.

Wonder what Strange, Currie, and other manufacturers say about it?

pla-tym

I called Moser today (7-11) and they said that with the tru-trac, you can use synthetic because it has no clutches, it has helical gears.
With the Eaton posi, you must use petroleum gear oil, because synthetic will give unnecessary wear on the clutches.