bullcrew

OK per Detroit this morning recomended fluid is Dino either a shell or coastal with no friction modifiers (says good for car truck diffs/ as a top off for LSD) 80/90 wt (for colder climates) 85/140 (warmer climates).
Apparently it gets full traction as its what they speced them with, I had amsoil in mine and just swapped to the coastal and when throttling in the dirt and gravel I can definently tell a difference. Both marks are predominatly deeper and more consistant, plus it was a bit quieter. I did the same spin there with the amsoil and one comes in light and stays a fair bit lighter than the other.
Multiple burnouts, donuts and mud pit passes and theres a big difference between the 2 gear lubes and how the TT reacts.

So Dino: Quieter, Both marks and grab significantly deeper and aggressive
Synthetic: noisier and one mark less significant and eased in more gradual.

Matt16

What weights of oil are you using?

bullcrew

80/90 is what they recomended for the climate here (0 at night and 25 as a high in winter).
I wanted to run a thicker oil (85/140) in hopes it would grab even better but was told it would be too thick!
Now if you have some insight to that Id appreciate it!
Does thicker oil hook up better/more torque? Its not noisy at all I just thought it would have an even more effective LSD action.

Matt16

As I understand, you can't hurt anything thicker oil. Its just going to be less efficient. I'm using 85W140 and its fine, with no noticeable loss in efficiency. I doubt its any different with a Truetrac. Why don't you try cheap oils in a thicker weight, that's what I did with my Aussie until I found what I liked. The advantage to a thicker oil is better protection.

It would be cool if you posted a video of your truck driving off road in situations where open/ open would likely get stuck.