Noisy trutrac differential

[lmoengnr]

If they used the motive brand diff gears they are noisy, got the diff rebuilt in my old vx ss with a true Trac and 3.9 gears new bearings etc and it was noisy right from the start due to the diff gears

Motive are the only suppliers of 4.11 ratio ring and pinion gears for ZF diffs.

 

[Immortality]

It's because most aftermarket diff gear sets are primarily made for motorsport use where noise isn't an issue.

 

[Robert Dawson]

Motive are the only suppliers of 4.11 ratio ring and pinion gears for ZF diffs.

Thanks for your insights. I may just have to live with the noise.

 

[Robert Dawson]

did u keep the factory diff rubbers or upgrade to more solid ? even with my standard diff 3.7 i changed mine to street semisolid and got a heap of noise so went back to factory and silent again

Not sure what diff rubbers were used.

 

[VTS5]

Thanks for your insights. I may just have to live with the noise.

NO you don't have to...We do those conversions all the time,,and we ONLY use Motive Gears,ZF's gear setup , shimming and pinion setup is VERY important and tricky , not every1s cup of tea,specially so called mech's.we do their dirty work,including few dealers.
Long story short.......
You should have a very quiet and smooth running diff,regardless of the ratio.We mostly install 3.7 and 4.11
We also have PLENTY ex GMH stock,LSD SINGLE

 

[Immortality]

What backlash do you guys recommend?

 

[VTS5]

What backlash do you guys recommend?

8 to 10 will give you nice quiet strong setup...Good quality full syn. oil is also very important..
I must add,every different ratio requires different approach to pinion setup.Pinion shim thickness,crush sleeve length and condition,bearing type/brand etc.etc.

 

[Immortality]

I've mocked mine up with a solid pinion spacer, original pinion shim, dialed in .009 backlash and it gave a nice wear pattern. This is all on a M80, new bearings, 3.73 motive gears with Eaton trutrac centre. Now I need to finish stripping it all down, clean and fit seals and do the final reassembly.

Interestingly, I'm sure the Eaton instructions said mineral oil?

 

[villn808]

8 to 10 will give you nice quiet strong setup...Good quality full syn. oil is also very important..
I must add,every different ratio requires different approach to pinion setup.Pinion shim thickness,crush sleeve length and condition,bearing type/brand etc.etc.

Eaton and Harrop both recommend mineral? 80w90,

Although I’m using Penrite 85w110 Pro Gear mineral.

 

[VTS5]

Interestingly, I'm sure the Eaton instructions said mineral oil?

You can use whatever your heart desires..Olive oil if u want,it's your diff not mine,I wouldn't put mineral oil into our customers differential,
Unless it's a single spinner B/W or full spool(smaller size carrier/s more space in the housing)
It's no brainer,,syn. oil outlasts and outperforms min. oil.
In simple terms;;
In small housing,spinning thousand time a minute,churning gears creates lots of aeration and foam/air bubbles,straight into the meshing gears gets compressed(bang) creates heat and wear.
Syn. oil will typically have a film strength 5 to 10 times higher then min. oil(less gear wear),
Syn oil simply more tolerant to extreme heat then petroleum based oils are,
Syn oil flow much much faster and better then mineral oil,therefore your expensive pinion bearings won't be starving for lubrication and your carrier bearings won't be dancing in their cups.
Mineral oil requires more service (2 to 1)intervals,
etc. etc. etc..

OIL, .lubricates it..For quiet and strong performance, diff centre,should be setup properly first...