Help with Differential problem on 1957 Transtar (3E7) - twin traction

[tim mccracken]

Hi folks. Unfortunately my first post here is a cry for help!

I acquired a '57 Transtar last year. No problems for the first months of driving. Then a clunk started from the rear-end when going through a corner with any throttle applied. No noise when coasting through the corner. Yes - this is a TT (Twin Traction) differential. After months of too-much-work and not enough time to look at it myself, I took it to a good local mechanic.

The short of it: tips of gears are chipped and one pin is broken. This is in a Dana 44. it turns out that this is one of few years where the axles are tapered and 19 spline. Talking with Studebaker West there are no new parts for this. While the Dana 44 was used for years, the newer ones have different splines.

Since I will not be taking this off-road, I am thinking that it is a good time to move away from the TT. It also seems like a good time to a lower gear ratio - this one is 4.27.

What are my best options?

I can start the search for another diff or full axle from a 3E7. (Let me know if you have one, or know someone that might!)
Are there any other easy swap-ins?

I throw myself on the mercy of the forum!

Thanks,
Tim

[DieselJim]

Dana 44 is and have been used by Jeep. Any 4 wheel drive shop should help you out. I have changed the ratio by using a set of gears out of a car. Making sure it is a 44. Changing all parts, including the pinion bearings, cups {races} and shims. Good luck.

[RadioRoy]

Welcome to the forum, Tim.

Does the truck have overdrive? What ratio were you considering?

[StudeRich]

Be careful changing the Ratio to a Higher Ratio (Lower as you call it [Numerically]), most of these 1957 & '58's were only 259's, not the more Torquey 289's and the Trucks are Heavy and designed to carry Loads.

So if you have Overdrive and you get too crazy with the Ratio you will have to downshift a lot to Direct, to pull slight grades especially if you Load it, or Tow with it.

A 3.73 MIGHT be a good choice for you, depending on your driving Type and Style, if you don't Haul much.
And, IF you DON"T have Overdrive, it might be time to get it, and leave the Rear Axle Ratio at 4.27 or 4.09.

[JoeHall]

Depending on the transmission you have, now is a good time to dial the rear gears in for modern roads. If you have a T89 with OD, a 3.73 would be fine. If it is a T89 without OD, a 3.31 would be OK. That is, assuming you do not plan to do much heavy duty hauling with your truck.

[DieselJim]

Tim, I responded to your message. It would not post. To answer your question, the splines are the same.

[tim mccracken]

Thanks everyone for the input. A few responses:

Welcome to the forum, Tim.

Does the truck have overdrive? What ratio were you considering?

It does have overdrive. I haven't gotten to the point of figuring what ratio I might want, but happy to get suggestions.

Be careful changing the Ratio to a Higher Ratio (Lower as you call it [Numerically]), most of these 1957 & '58's were only 259's, not the more Torquey 289's and the Trucks are Heavy and designed to carry Loads.

So if you have Overdrive and you get too crazy with the Ratio you will have to downshift a lot to Direct, to pull slight grades especially if you Load it, or Tow with it.

You are on the right track - My engine is a 259.

Depending on the transmission you have, now is a good time to dial the rear gears in for modern roads. If you have a T89 with OD, a 3.73 would be fine. If it is a T89 without OD, a 3.31 would be OK. That is, assuming you do not plan to do much heavy duty hauling with your truck.

My transmission is marked with a T85C-1A. Overdrive is marked R11-G.
When you say "heavy duty hauling", I assume you mean a heavy trailer?
Do I want to be able to fill the bed with wood and drive comfortably? Yes. Might I connect a trailer and move something heavier around town? Yes. A light boat on a trailer - possibly. Do I think I might move 5000 lbs on a car or boat trailer ? Nope.

Tim, I responded to your message. It would not post. To answer your question, the splines are the same.

I am not sure I follow you - the same as what?


Thanks again everyone - the quest continues.

[Mrs K Corbin]

whatever you do, don't toss the old TT diff, some one may want it for parts, etc.

[nels]

I doubt your splines are bad. The pin that is broken must be the centering pin, if it’s really broken. These fall out quite often when you pull an axle. What gear is chipped the pinion or ring? Sometimes the ring can be chipped and not really hurt anything as far as noise and drivability. From the symptoms you mentioned it sounded more like your twin traction lubricant was worn out. Its amazing the noise they can make, especially in a turn, when that additive is bad.

[DieselJim]

I was sent a privet message asking about the axel splines. Thought it was from you. Went back and looked. Was not. Sorry for the confusion. Seems to be my state of mind any more.

[tim mccracken]

OK - I got a little more info - some of the teeth have sheared off the spider gear(s), and one or both of the cross-pins are broken. Metal has circulated through, so there are impressions on the other gears. It doesn't sound like the internals are salvageable.

So... It seems like options are:
1) All new internals, new diff and custom shafts (because the coarse-spline is no linger available). I asked for a quote. Expect I wont like the $$
2) Find a used differential from the time period with coarse splines. I am thinking an open diff and gear ratio in the 3.73-4.09 range. (any leads on someone that might have?)
3) Find a full hub-to-hub replacement from another 3E7. (any leads on someone that might have?)
4) Find/adapt a full hub-to-hub setup from another vehicle - later Stude, Ford, ?? My preference would be stay stock, or close, but wondering if there is a good option here. I'm not sure how to go about this - any thoughts?

Thanks for the help folks.

[DieselJim]

I have a 4:09 tt gear set as removed from the rear housing. Has the bearings and shim pack in place. I'm currently in Florida. Won't be home until the 19 th.

[Pop's Chariot]

I have a 4:09tt rear out of a 57 truck with no hubs or drums. I decided not to put it in my 49 turbo champion truck. I would just like to get my money back out of it. PM if interested I'm in California

[DieselJim]

I have a 4:09tt rear out of a 57 truck with no hubs or drums. I decided not to put it in my 49 turbo champion truck. I would just like to get my money back out of it. PM if interested I'm in California

There you go, Tim. Just change the gear oil, pack the axel bearings, install your brakes, bolt in and GO.

[jpepper]

The standard Dana 44 used 19 spline axles up through the mid 60's. They then transitioned to larger 30 spline in the late 60's. Your differential case is a "4" series meaning it is made for 3.92 and up numerical ratios. Anything lower than that requires a "3" series case. I think in your truck I would use a 4.09 or 3.92 ratio. You can get parts to repair the TT unit and you can buy a R&P kit which includes all necessary parts. When rebuilding the TT unit replace the bolts holding the two halves together. I use ARP fasteners on them. Parts can be purchased from DTS https://www.drivetrainspecialists.com/index.html , National Drivetrain http://www.nationaldrivetrain.com/ or Motive Gear https://www.motivegear.com/ Your OD ratio is .7 so a 3.92 gives you a final drive of 2.74 and a 4.09 gives you 2.86. 2.86 final drive puts the engine at about 2500 RPM @ 70 MPH depending on tire size. Your 4.27 ratio has a final drive of 2.99 .