View Full Version : Twin Traction Troubles

07-25-2005, 04:07 PM
I've been picking up a vibration in the rear driveline of my 62 GT Hawk (w/auto & TT rearend). I recently replaced the left rear axle which was bent and the U-joints (see recent thread). I filled the rear pumpkin with standard Hypoid gear oil and added a can of positraction lubricant. I also installed new rear shocks and tightened up the spring mounting u-bolts which were loose on the side where the axle was bent. The rear brakes have been redone as has the e-brake system. Yesterday I took it for a test drive and at first it seemed to operate just fine. I drove it at 40 to 50 mph for about 10 miles, however when I slowed to 25 in a village the rear end felt like it was going over a washboard road (which it wasn't). After leaving the village I brought it back up to highway speed and it was smooth as silk. On the way back home the same vibration occurred at low speed. Does anyone have any thoughts as to what the problem is? Could it be the clutch package in the TT rearend? The car sat idle for quite some time, is it possible if I drive it more the problem might go away. Would adding more positraction lubricant possibly help?Thanks.

1960 Lark Convertible
1962 GT Hawk

07-25-2005, 08:35 PM
This is gonna sound stupid, but do your rear tires match and/or are they inflated the same? Gotta check the simple stuff before you freak out.


55 Commander Starlight
62 Daytona hardtop

07-26-2005, 05:37 AM
Thanks Nate, the tires look okay. I'm going to try a tube (7 oz.)of "Trans-X" posi-trac limited slip gear oil additive. It claim it "Prevents Chatter, Jerking & Slipping" Probably just snake oil, but you never know.

1960 Lark Convertible
1962 GT Hawk

Mike Van Veghten
07-26-2005, 10:16 AM
Just a note, those posi additives are for tight posi's that "chatter" when going around corners....
The clutchs are just going for a "ride", "no slipping", when going straight down the road and no additional high load power is applied.
As N8N says, the tires "need" to be the same diameter and have the same amount of air in them.

I'd also look at you driveshaft...u-joints installed properly, seated properly and greased?

charley norton
07-26-2005, 11:29 PM
I had a 51 chevy that did something like that. It sat for about10 years before I bought it. Turned out it was rust that was on the gears not submerged in oil while it was sitting. It was just a work truck so I kept on driving it. It actually got a little better, but never quite went away. I didn't want to spend $600 dollars on a truck I paid $400 dollars for. I'd put it on jackstands and give it a run in the air to see what produces itself. You'll need a helper

63 R2 Avanti