Wow, there was 4 speed auto trannies in 1957?!!? I learn something new everyday.

It might not be the best tranny in the world, but it a far cry from auto trannies from 50 years ago. Go to one of the Duramax forums. You'll find that the Allison isn't really all that great either. It does have better towing characteristics stock VS stock, but it also has it's problems. When these problems arise, they are much more costly than on the 48re. Also, once you start modding the truck, the Allison is in need of upgrades just like the 48re.

 

[QUOTE=omaharam;1691292]Wow, there was 4 speed auto trannies in 1957?!!? I learn something new everyday.


Not fom Chrysler but from GM. The four speed Hydro came out around 1950.

The three speed Torque Flight tranny from Chrysler replaced the old two speed tranny in 1957. It was the big upgrade. Today it's the same basic tranny with no rear pump and a tacked on OD to give it the 4th gear. The three speeds were all there was till the Cummins came along and didn't have a wide enough RPM range, so Chrysler added the OD. That's part of the problem, the 4th gear is so different than the rest and the shift is weird. It's just been upgraded over all these years. Time for a modern, well thought out, more seamless design. In fact the 68 is WAY overdue.

For heavy towing or four wheeling, a nice low gear and torque converter is the way to go. Even spaces between gears and 6 speeds allow the right gear for any condition. Shifting characteristics that makes sense between each gear instead of 3-4-lockup in one slipping motion with a huge RPM drop . Being able to hold any gear and lock up the converter when wanted would be frosting on the cake.

The 48 is only good for stock power and light loads. And yes, it is a 50 year old design with some upgrades. And all the performance uprades you see people doing to make these things strong enough are not rocket science. They are just better materials that would have cost Chrysler a little more to build themselves. Or, is some cases, Chrysler parts that are off the shelf and were not used for cost reasons. Like the roller rear thrust bearing and the heavy intermediate band.

I'm not saying the whole thing is junk, but it could be a lot better. When I tow in the mountains I am always aware of it and trying to compensate for it. I've put in $2,000. to make it just good enough for the light power upgrades I've done and the work I do. One day I'd like to upgrade tp the 68 or the Aisin. We'll see.


John

 

Well guys I just go back from my trip and I have to say bad news. I have been towing in the range of 12k-21k on top of my 9100lbs PJ gooser and lets just say my tranny has had enough. I hate this tranny with a passion. I just got a hold of a six speed Allison and I was wondering if you all know anybody who has done this swap and what parts are needed?

 

I think ATS makes a conversion kit. You're still going to need to upgrade that Allison unless you leave your Banks off while towing that kind of load.

 

The stock 48re is not that good when towing heavy but it works. I don't care for it but I am living with it until my powertrain warranty is gone. The main reason I would consider a new 6.7/6speed auto would be because of the tranny and exhaust brake. Going to the mountains pulling heavy next week so we shall see if the 48re will come back in one piece.

 

6-speed allison will not work as a conversion right now. I dont know if the calibration is possible with the A40 4th gen TCM.

 

From what I understand the difficulty with the Allison connected to the Cummins in A Dodge is the controller. This swap has been tried and no one has beeen satisfied with the way the trans shifts.

You need to test drive a swap before making your decision.
good luck

 

As I said, spend your money on upgrades for the 48RE. Forget the Allison.

 

I say forget the Allison too. But the 48RE is always going to be a four speed.

I'm thinking Aisin or 68 RE. I hope those are the future transplants.

John

 

When you bought your truck you should have looked at a 6.7 cab and chassis with the Aisin transmission. I'm at 73,000+ miles with no problems. I hotshot and pull gross wt loads up to 23k, the max our company will allow on a gooseneck. The Aisin transmission handles it with no problems.

 

Im curious to know if the aisin will bolt right up to the 6.7!!!!!!!!!??????? Or what you would need for it to bolt up. I know nobody broke there 68's yet but if mine breaks under 100k miles, maybe its worth upgrading to the aisin if possible, but decking out the aisin before dropping it in, and then sellin my 68 rebuilt!!! LOL, just an idea?!?!

 

I'm sure it will bolt right up, seeing how it is on a 6.7 to start with, but I doubt the computers will talk to each other. That would probably be the main problem.

 

Please let us know how that 6 (six) speed allision swap goes. It will be an interesting swap!

 

Ill take my old outdated 4 speed over an allison

Eric

 

Allison swap will be two or three times the money and no better than an upgradrd 48RE. Frankly, you bought a pickup tranny, not a Pete or Topkick, or Freightliner. You are using it for other than it was intended, or you paid for. Quit complaining about the tranny and upgrade it. It can be built to work for you. Stock Allison will do the same.