Diff gears

[Bulletz12]

Cheers guys also what oil to best suit Eaton Trutrac?

 

[Chuckmeister]

That doesn't make sense?

Maybe you are referring to how the gears are lapped in? My Motive gear set was factory lapped but was still noisy, I'm sure it was my fault as I didn't have the correct pinion shims and so the pinion height is slightly off which made the gear depth/mesh wrong.

gawd...I have to stop posting at 3am with a bottle of jacks under my belt...15 things on my mind with my car atm lol Diff gear whine being one of them

I believe he was suggesting that its the way the gears are cut and the machines that do them. One side is cut better and are quiet on acceleration while the other side is noisier under deceleration or no load..

I'm happy to find out the issue as much as anyone as mine under no load sounds like a freaking race car.

 

[Pollushon]

I've got a 3.9 Eaton Truetrac behind a T56, no real discernible noise aside deceleration like chuck said. I will say with big power 1st becomes pretty useless and you're smashing out 4 changes before you hit the traps. A S1 sequential greatly improves that with insto-changes. Otherwise loads of fun

 

[rickybobby]

re truetrac oil type
GL5 rated 80w-90 gear oil
one of the benefits is that you don't have to hunt around or pay more $$$ for LSD / synthetic oil
i have two of these (truetrac) in two different cars, one with factory gears and one with motive gears
i didn't, and still don't, really know what I was doing re diy diff building but for me
- factory gears were easier to shim to a nice pattern and super quiet
- motive gears were noisier (only a little bit) and difficult to shim (hard to find sweet spot for nice pattern e..g. 1 thou too deep, 1 thou too shallow, etc.) and i had to compromise with a slight whine on de-acceleration
either way they're both great and heaps better than factory lsd, single spinner or spool
spool is pretty impressive but slow corner stuttering, damaged driveshafts and noisy parking did my head in after a couple of years which is what i was warned about but i had to learn the hard way

 

[Stephen Bartlett]

I'd choose a gear set your happy with, I'd go 3.9's but I'd choose Dana as they are generally alot quieter that Motive. I have a 3.9 set in my car atm and it has a really nasty deceleration whine. Will go back to Dana in time.
Harrop for the truetrac.

Hi I was thinking of putting 3.9 in my crewman. Now I’m thinking 4.11. I wanted more grunt taking off. What do you think

 

[Fu Manchu]

I had 3.46:1 in my VP ute. That made it fun to drive. 4speed auto.