Technical How to rebuild a quick change differential?

The differential in my quick change is a gear type and it's posi function is not very posi. I am going to have to open it up, but I don't want all the magic to escape. Has anyone ever rebuilt one or have an exploded view laying around somewhere?



-Abone.

 

Does it have clutches? If so you can polish the steels and replace the friction discs.

If it's a gear only type(Detroit true trac) there is nothing to rebuild. They will rotate freely by hand but won't under torque.

 

Hey "dumprat" He said that is the "gear" type posi..!
NO...clutches used.

flame -
I wasn't aware that that type posi required any rebuilding ? Unless the bushings are loose and the gears are rattling around inside.
I have a similar unit in my Winters Quick Change. It does not act like a clutch type unit in many circumstances. This includes having both tires off the ground. Spin one tire one direction, the other tore spins the opposite, like an open differential.
It's just the way they work.

Mike

 

Mike. I have the same differential in my Model A and if you turn the pinion, you can’t hold the tire from turning.

The suspect unit acts like a regular old single spinner. If you turn the pinion, you can easily hold either tire, no “posi” effect at all.

-Abone.

 

Mike VV don't be a dickhead.

There are several gear type units that look like this but are different inside. Flamed. Can you see inside it? Are there springs of any sort?

 

Easy now!! This can be a great technical thread(pics) and the experts sharing their knowledge. Pete

 

Any tech is good tech. I am in .

 

Here is what I found.



I didn't find shit. The differential I put in the quick change and the spare I had laying around looked exactly the same inside. Nothing out of the ordinary, just a bunch of worm gears doing what worm gears do. I'm going to put her back together and let her fly. If it only peels one tire, I'll take it back apart, but I think she is going to be OK. At least now I know how they work and am not scared of them anymore.

See ya, -Abone.

 

Here's a youtube video of Eaton Tru Trac video that show's how they work.

 

Yup exactly. I have had one of those apart to weld repair and remachine the bearing journal where it cracked. On the bench they seem like an open diff. They are unnoticed on the road, until you walk on the throttle. Buddy cracked his sidestepping the clutch with one tire on pavement and one on gravel.
His was in a 9" ford,.

 

Abone,
Sorry I haven't been on all day. Got your PM just now.
Looks like you uncovered all the magic in that Gold Track.

I believe that is a Dan Press unit. He got everybody all excited with the Gold anodizing. There are several units that are virtually the same in function. The only bad thing is that the parts don't interchange between manufacturers. I believe that Winters did use some gold anodizing on some of their units but the color was somewhat different. Winters now anodizes theirs in red.
You may see some markings like "1/2 AT" If so, I'm sure it is from Dan Press. They denote how 'tight' the unit was set up initially. This all has to do with breakaway torque to let the unit differentiate in a corner (circle track stuff). Not necessary or desirable on a street car. Some units were made adjustable with Allen set screws preloading the thrust plates. Don't see those on yours, but some other guys reading might have one like that. If so, you want to back them off for a street car.
Dan is no longer with us and the guy that has the business (DPI) does not make these anymore. Some parts may be available, but you have to send him a sample so he can match it up. The helix and shoulder diameter on the gears changed over the years.

Although they are pretty tough, check the planet gears and side gears for pitting and broken teeth. Also, the thrust plates can crack.
I have never seen one crack as Dumprat described.

Now everybody can fix them