gm 8.6 truetrac

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I have a 2004 silverado with the 8.6 rear with a detroit truetrac diff. Eaton recommends dino oil with no additive. Currently using supertech 80w90. What is a good change interval on this oil? Would a 85w140 provide more protection? This is a daily that doesnt tow.
 
You can run synthetic gear oil with a Truetrac as long as it doesn't have "friction modifiers" in the fluid.
I run Redline 75w90 N/S GL-5 in my Dana 60 with a Truetrc.
 
Originally Posted By: Spitter
I have a 2004 silverado with the 8.6 rear with a detroit truetrac diff. Eaton recommends dino oil with no additive. Currently using supertech 80w90. What is a good change interval on this oil? Would a 85w140 provide more protection? This is a daily that doesnt tow.

OCI here in tropical climate is 25-35 k miles.
Yes, 85W140 would provide stronger wear protection and say goodbye to potential gear whines.
If you bother to infra-red the differential operating temperatures, 85W140 might runs cooler than a 80W90.
 
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The best way to know the proper interval would be to do a few UOAs. Perhaps run 30k miles and take a sample; check the vis and wear metals and TAN if so inclined.

Since these axles don't come with a TrueTrac in them, I presume you replaced with OEM diff (a G-80 gov-bomb?) with this Eaton TT? How fresh is the work? I ask only because you may see elevated metals if there were new gears installed with the diff. If the gears were reused, the wear won't be quite as high as they will already be worn in.

Yes - you can use syn fluids, but they will alter the torque-bias you are seeking. Same goes for FMs; you don't want any fluids that have LSD (aka FM friction modifier) in there.
 
Originally Posted By: mx5miata
Plenty of 80-90 choices out there


Just got a gallon of Delvac 1 75w90 for $32 ...
we have been through this before ...
 
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