TrueTrac Issues...?

[4wayair]

I've got a Detroit TrueTrac in a Moser 9" and have just over 600 miles on it. Pulled out of the driveway and started hearing a slight rubbing sound (like a tire rubbing on 1/3 of its rotation) when car gets over 5 mph. Fluid is full and have isolated the noise to the differential. I read some other posts on the web about TrueTrac bolts backing out etc... I bought the car out of state and didn't due the install so am not that familar with TrueTrac's. Was wondering if anyone else has had any issues with a TrueTrac or if there were any gotchas on the disassembly / re-install before I tackle it.

Thanks in advance for any advice.

[Scott Parkhurst]

I've had no issues whatsoever. Mine is quiet and works great. Yours should too! I have a heavy car (3,700 lb 4-door wagon) with good power (545 hp, 500 ft lbs on the engine dyno) and a T56, and I drive it hard on a regular basis. If anyone was going to have issues, it should be me. I have not, and I love the TruTrac because it takes the abuse. Once it's right, yours should be trouble-free.

[chicane67]

To diagnose this a little further... and to be sure that it is something in the center section...

Jack it up, put it on stands, pull the wheels and tires... re-install the wheel nuts to bolt the rotors/drums to the axle. Have you/someone start it up an re-create the load that was producing the noise, while you/someone uses a stethoscope to pin-point the noise.

If its not in the brakes, pull the rotors/drums and do the same thing. If its in the third member... pull it out and look for anything obvious. If not... and you are not comfortable with doing the work yourself, I would recommend that you take it somewhere that specializes in differential service to pull it apart, fix it and re-assemble.

Seeing that you live in in Arizona... I would recommend that you use a straight weight 90 at the minimum... (I myself would use a straight weight 140.) If you can get Schaeffer's locally, I would use their #209A with the suspended moly... or if a multi-viscosity in being used (or you cant find the Schaeffer's, there are dealers in Mesa and Phoenix)... I would use Torco's 85-140 RGO (available all over Arizona.)

Do not use a synthetic... use a crude or paraffin based oil product and no... you do not need to use any friction modifier.

[4wayair]

Turns out it was the rear rotor dragging on the caliper. Did replace leaking axle seal and diff gasket though... so got a good look at the TrueTrac. Neat!.

Thanks for your help!

[79MALIBU]

I've had no issues whatsoever. Mine is quiet and works great. Yours should too! I have a heavy car (3,700 lb 4-door wagon) with good power (545 hp, 500 ft lbs on the engine dyno) and a T56, and I drive it hard on a regular basis. If anyone was going to have issues, it should be me. I have not, and I love the TruTrac because it takes the abuse. Once it's right, yours should be trouble-free.

Nice Wagon! I like your style. I have a Tru-tack in a 79 malibu. It is setup with for Autocross. I have encountered a possible issue with my truetrac and thought i would run it by you.

I see you autocoss, so does the inside rear wheel ever lift off the gound on you?

Mine does, and when it does the torque goes to zero. This is bad for the true tack, becouse all the worm gears uncouple and make a ginding noise ( wich sounds exactly like a tire rub ).

How long habe you been running yours?
I have had mine a short while, I intend to ballance the car better, sometimes the wheel will lift. Has anyone heard any bad stories about the truetrac and autocross??