Rear Axle: TT Rebuild, Model 44

[JoeHall]

It appears it is time to rebuild the Twin Trac rear end in the 62GT, after over 300,000 miles. I've always been lucky enough to just swap a low mileage rear end in, so have never had to do other than routine maintenance on them. But I currently do not have a suitable replacement, which is a 3.54 TT. I want to stay with that ratio and TT, so looks like rebuild is most feasible. Focusing on just the TT component, I hope to gather the needed parts before tearing it down. I am guessing it is definitely gonna need clutch discs & plates, and thrust blocks.

Any other guesses as to TT unit parts I am very likely to need for the rebuild?

Thanks All,
Joe H

[bezhawk]

Check the cross shafts that the spider gears ride on, and also the clutch seats under the larger side gears. they may be galled on the back surface where the clutches ride. If the ring and pinion mesh are good, then you may get lucky by just replacing the case outer bearings and races and keep the shims in the same place. It's also a good idea to replace the 8 case bolts with new grade 8 bolts. When you got to put the case back together, slide both axles into the sides on the bench BEFORE you tighten the two halves together. If you don't then the side gear splines won't line up with the clutch seat splines, and when you get it back into the carrier, and go to install the axles, they wont slide in past the misaligned splines.
Randys' Ring and Pinion had the clutches last time I got them, and it was their Tennessee store. There are two different sets of clutches, mild and aggressive. I got the mild.

SI may now stock them too. I like the Ford additive the best.

[3rdGenStude]

I got my thrust blocks from Fairborn.

Paul

[3x2stude]

If parts do become a problem "Auburn" make a limited slip differential that will fit the Dana 44 housing.

JK

[JoeHall]

Though high mileage, this rear end has never been abused under my care. I will disassemble and inspect everything, but only plan to fix what is broken, and hope to get by with new thrust blocks, and plates & discs. I have been reading the Shop Manual this evening, and now think I may have damaged a thrust block or cross pin when setting up end play after repacking the wheel bearings recently. A trick I have always used is to install the driver's side axle first, including the backing plate. Then, to insure the driver's side bearing race is firmly against the backing plate, I give the end of the passenger side axle a whack or two with a hammer and brass drift. At that point, the end play is easy to determine accurately, and shim to spec. Maybe when I whacked the axle it damaged a block or a pin, but that has never happened before.

The reason I say the above, is because I am gaining end play, after a few hundred miles, and some strange noises from the rear end I never heard before.

Thanks for all the info folks. This is an unforeseen PITA project I did not need, but plan to tackle it this weekend. If it needs much more than I anticipate, might as well toss this rear end and look for another one, as they are still fairly thick on the ground. Meanwhile, I have a conventional, 3.31 to swap in for the interim.

[dpson]

Joe,

I may have some NOS parts if you want to go that route.

[Mike Van Veghten]

There's a whole host of "posi" units that fit those housings if you can't come up with parts for the original unit.
Look into offroad dealers. I had Currie rebuild mine with ALL new guts, including the full gear design posi type carrier for my Dana 44.

Mike

[jackb]

recently I had a creeping excessive end play in my 44 R/A. Turned out the axle tubes were loosening and spreading out....

[wdills]

I have nothing useful to add to this discussion, this question is just for my education. It seems that 3.31 Twin traction rear ends are the most common. If you had a bad 3.54 rear end and any ratio good rear end up to 3.73, couldn't the limited slip "stuff" be swapped from one to the other? Or maybe it would be easier to swap the 3.54 ring and pinion into the other rear end. Would this be any easier than a rebuild like Joe is planning?

[sweetolbob]

I have nothing useful to add to this discussion, this question is just for my education. It seems that 3.31 Twin traction rear ends are the most common. If you had a bad 3.54 rear end and any ratio good rear end up to 3.73, couldn't the limited slip "stuff" be swapped from one to the other? Or maybe it would be easier to swap the 3.54 ring and pinion into the other rear end. Would this be any easier than a rebuild like Joe is planning?

Just me, but I think 6 of 1 - half dozen of the other. My 74 Avanti had a 3:2? nonTT rear end and I had a 3:54TT on the shelf. The original Avanti 44 had about 100,000 miles on it and the 3:54 had unknown TT quality so I still had to rebuild the TT and also buy a bearing kit to install it. So the clearances all had to be reset anyway.

Secondly, 44 gear sets back then were stamped with a +/- to indicate clearances and match the R&P units so unless those marks also matched you would also need to re-clearance the setup.

I guess a lot of words to say what I said initially, it's essentially a rebuild either way.

Bob

[(S)]

Last I checked, The clutches were scarce. Between Randy's and another source, we got a case of Dana ones. I would think they are re-poped by now, but if you want real Dana, I have one.

[JoeHall]

I did not go into the pumpkin today, but instead went back and double checked my recent work, and dialed end play down to about .001". Afterward, with tires mounted but off the ground, I discovered the driver side has a noticeable wag on the inboard end of the axle, maybe .100". So definitely need to go into the TT unit and fix whatever is worn out and/or broken.

However, with brand new Auburn posi units available for $307, including shipping to my door, am tempted to just swap one of those in. Have done some reading on line, and they are real good units, as long as not abused too much. Main complaints are from folks with mega HP motors, and wanting both wheels to keep spinning when doing doughnuts on asphalt. I do not abuse my Studes like, so not an issue for me.

[sweetolbob]

I have the Auburn unit in my 83 Avanti 44 with the 355 roller motor, 4:10 gears and probably wider tires than you run. It's survived so far.

Bob

[JoeHall]

I spent Sunday swapping in a conventional drive 3.31 rear end, and just took it out for about 40 miles this evening. Replacing the 3.54 TT has just moved waay down on my priority list. The 3.31 is quiet as a mouse, and drives out prefect on the highway. Only thing left to do is dial the speedo in a little closer.

The TT failed prematurely, but I am hopeful the conventional drive 3.31 will hold up better.