Does any one here know what Allison I should be looking for? I want to use it on my 4x4 gmc this next summer. I have recently put the Cummins in and love it, but I would like to have a Allison in it some time this next summer.

 

The 545 Allison is one of the last mechanical transmissions for medium duty use. It was used extensively with the ISB, 6B and 3126 Cat engines so a bellhousing shouldnt be hard to find. However, I am not too high on this transmission and to be honest I dont know many who are. These are known to be troublesome and basically a throwaway trans. If you stepped up to the 1000, 2000 or WTEC series of Allisons you would run into alot of trouble with the electronics since it is an electronic controlled trans with its own control module. A datalink between the engine, trans, and ABS module is also vital with these models. The smaller Allisons arent all they are cracked up to be.

IMO you would be time and money ahead to opt for a performance transmission from a reputable dealer.

 

At the presn't time I have a 350 turbo on steroids, and have been told it wouldn't stand a chance. This trany was custom built for the job for a grand total of $3500 and it hasn't had a problem yet. However I don't think it would hold up for more than a year. It was ordered from Nascar Transmission in North Carolina, and was rated for 500 H. & 700 lbs. My bigest problem was with the vacuum. How to make that work? 350 turbo shift acording to vacuum. An in dash adjustable regulater with guage does the stuff.
But I've herd that Alls were the way to go! And I was just looking at a AT-545 crate trans. No the way to go you think??

 

Well, im not going to steer you clear of it, but be aware that the 545's limits will not be far from 700ft lbs. Allisons larger transmissions are tough, but the medium and light duties leave alot to be desired. Why not go with a DTT or ATS auto trans?

 

Which Allison Tranny goes in the Blue Bird School Buses? Assume that is med duty...thought that one was a success? A duramax mechanic told me he was pretty sure that same trans was the one in the Duramax...anyone know?

RJ

 

The school busses do not lock up, and there are torque convertor problems according to a friend who has a fleet.

I second the DTT, ATS, Goerend, etc. suggestion.

 

The 545 tranny was designed for a gas engine but has also been used on small bore diesels as well. They do not have lock-up, And the torque convertors are the weak link. They are rated at 190hp and I think around 560 torque not very much. The 1000 series is a lookup and is used on the Duramax Diesel it is a full electronic transmission. The 2000 is the same but is a bigger unit and is used in medium duty applications. I would do as the others
have said and get a after market tranny and stay away from the 545 as they are big and heavy and not much good.

 

I don't know what a DTT, or ATS auto trany is. Whats this about a allison converter as a week link? I was told they were tuff. A&Redds trans comp. has me using an allison converter in the 350 turbo! Am I to expect a problem?? They said it was a lot better than any other one I could have bilt.

 

ATS and DTT are some of the top names in trannys people use for the dodge cummins aplication, from what i've seen, the guys who have mucho HP all seem to have one of those so there must be somtin good about em.

 

The Allison trans in the Duramax is not that good of a tranny. I saw the clutches out of a burnt up tranny and was disappointed. I expected the clutches to be big but were pretty small. IMO I would steer clear of Allisons. When these trannys go out of warranty you will see alot of unhappy people. The rebuild kit was outragous.

 

Check here http://www.dieseltrans.com/ ....nice people and a great tranny!

RJ

 

I'll do lots of home work before I get into the $$$$ part of it, and I will look that web site over tonight
Thanks

 

The 545 was behind the 7.3 in school busses I have one we were going to put it in a project truck butchanged our minds.Had a mt40 in my pickupit shifted to hard when I wasn,t loaded I would bark the tires every time it shifted. Took it out to put aRTO6610 10 speed in.If you put the 545 in a light truck it should do ok.

 

Where is the MT 40 now? Would you sell it ? What about a trans case?

 

I traded it 5years ago for some other parts that MT40 weight is the same as my 10 speed it is castiron 6sp no overdrive.One of the guys at the salvge yard put the 545in his Ford 7.3 with 38 tires so he didn,t need overdrive trans, did real good firm shifts.he ran it real hard all the time.We have the 545 setting in the garage that one is alum,a hack of lot lighter
Dale