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inviolet
06-10-2011, 09:53 AM
Anyone have an issue with the TrueTrac having to much play in the yoke that connects to the drive shaft on the rear end side?

I have a new Detroit TrueTrac with 355 gears installed in a Chrysler 8.75 rear and every time I shift or push the gas lightly you hear a bang/thud coming from the rear as if the drive shaft had a bad universal. Both universals are good; the play is in the yoke on the rear. You can move the drive shaft about a quarter turn before the rear tires actually begin to move. Other than that noise the rear is quiet, Is this normal for a TrueTrac?

wmhjr
06-10-2011, 10:40 AM
Nope. No issues. You do realize that pretty much any tranny you get is going to have a bit of that driveshaft turning slightly before wheels move right? Other than that, I have zero noise in my Moser 12 bolt rear end w/TrueTrac.

John Wright
06-10-2011, 10:52 AM
Might want to check the pinion bearing pre-load......

Nessumsar
06-10-2011, 11:49 AM
...or pinion/ring pattern. The open carrier in my Nova has the same issue (pinion has 1/4-3/8" play). Did you install the new gear set?

pedro
06-10-2011, 01:32 PM
I have a lot of play (not a quater turn, but a lot) and get a thunk during shifting. I thought there was something wrong with the dif so I pulled the cover off to check backlash. It was obvious right away all the play was in the trutrac, backlash was right on the money. The rear is a complete 12bolt setup from moser.

I found a lot of stuff about play in the trutrac on the internet so I assume its common.

Pete

chicane67
06-10-2011, 05:34 PM
...or... learn a little finesse' to shift better ?

GNon18s
06-10-2011, 08:27 PM
I haven't had any issues with the Trutrac I've had in my daily driven jeep for around 5 years now. Also, some slop in the drive shaft sounds normal to me. I would pull the rear cover and verify the backlash is within spec.

AUTODYNAMICS
07-03-2011, 03:06 PM
I think its the loose nut behind the wheel have it looked at

eddiep
07-03-2011, 04:53 PM
I've broken several torsen units at the strip and the "thud" you are describing is a textbook symptom of a broken torsen diff. My car was usually drivable (just the annoying thud), but keep in mind you are taking an awful risk putting miles on it like that ... good chance it will grenade/lock up sooner or later.