Rear Axle: Posi Rear Identification

[bills57hawk]

My 57 Silver Hawk rear has 44 stamped in the web. There are two tags on the cover bolts, one with the letter T stamped on it and 43/13 stamped on the other tag. I always believed a sign of posi track rear was while on a lift if you spin one rear tire the other will also turn. Only the tire I spin turns. Do I have a posi rear? Does the axles only lock under torque? I did take a picturee of the rear with the covber plate off and can sen if that helps .
Bill

[64studeavanti]

Both wheels turn the same direction with the TT on my 64 Avanti.

Sounds like you have open R/A.

The 43/13 is the ring/pinion gears giving a 3.31 axle ratio.

A picture could help make sure.

[yeroldad]

If only one tire turns, it's not a posi. If both turn the SAME direction, then it is most likely a posi, unless the spiders are really worn. 43 divided by 13 gives you 3.071, which is commonly called a 3:31 gear ratio.

[r1lark]

Pull the oil fill plug in the back cover. If you can stick your pinky in the hole and wiggle it all around, it's not a Twin Traction. But if you stick your pinky in and almost immediately hit a solid object, that's the Twin Traction unit, so it is a TT.

While you have the plug out, add lube if needed.

[studejohn]

You most likely do have a positive traction unit Just an earlier model They used two different type As far as getting your finger in the hole on the early ones, you can. If you take the cover off, the unit resembles a Detroit locker Unit.
all earlyunits came with a T tag on them. Later units came with 45 A or B or C tag on them

[bills57hawk]

Here is a pic of the 57 silver hawk rear.
BIll

[bills57hawk]

Given the rear is not a posi, anyone know how to change over to a posi? Dose someone provide the internal gears etc allowing the use of the stock tubes, differential housing etc?
Bill

[Ross]

The picture you just posted shows that it is a posi.

[64studeavanti]

Agreed, looks like a limited slip "twin traction". Since the other wheel does not turn, you may need a repair.

[StudeRich]

How important is it to you to know if you have a TT, other than knowing the proper Gear Oil and Additive to use ?
Doing any Drag Racing or driving in deep snow ?

[Topper2011]

Given the rear is not a posi, anyone know how to change over to a posi? Dose someone provide the internal gears etc allowing the use of the stock tubes, differential housing etc?
Bill

Yes, Auburn does make one for a Dana 44 with the 19 spline axles. I have one in my GT dues to severe damage to my TT unit. If you go that route, make sure of your gearing as that does make a difference in the unit you need.

[64studeavanti]

Bill, O.P., has Twin Traction R/A. It may need repairs as both wheels should turn in the same direction. Bill, do you know if both wheels turn freely? Maybe a locked brake?

[bills57hawk]

O.P. has twin traction R/A???
Both wheels turn freely, everthing brand new with rear brakes and drums. I did install a mild 350 with a trubo 350 tranny as the original 289 was replaced with a 259 sometime before i bought the car. Do not plan on drag racing, snow, etc. Would be nice to have a posi. Is it possible the other tire only locks up when torque is applied?? Any thoughts how to diagnose and repair the current rear? Appreciate all the feedback.
Bill

[JoeHall]

Just to doublecheck if your TT is working: raise only one rear wheel off the ground; put transmission in neutral; try to turn the wheel that's off the ground; if it only rotates about 1/3 turn before locking up, the TT is working. If it rotates freely, the TT is not working at all. If it rotates but requires extra effort, the clutches may need attention OR the oil may have too much positrak additive. (The additive's purpose is to enhance clutch slippage so it won't chatter in sharp turns, but too much additive makes it slip excessively.)

[bills57hawk]

I will follow your lead and let us know how it turned out
Bill