Switch from Allison 643 to Allison 545

[the_experience03]

Why not run the 8.2 with the MT643?

[the_experience03]

The transmission issues are existent when it comes to the swap, but I don't think that should be a big concern for you at this point. The diesel repower is going to be what is expensive and difficult. What is your reasoning for doing it? I don't think you're going to gain much performance from the diesel swap really. You will gain mileage, but at only 5000 miles per year it might take a long time to pay it back. If you're really mechanically inclined I'd say go for it, but I think of myself as being pretty mechanically inclined and I know I wouldn't mess with it. You're talking about a lot of work when it comes to motor mounts, plumbing, wiring, etc.

[Elliot Naess]

Hard shifts /lockup???????
I have an MT643 in Millicent, and she shifts like a steady flow of chocolate martinis. Now... that AT545 I had in my first bus (RIP), that thing shifted like a #$%^&* sledge hammer!
It's an old but true Thing about automatic transmissions, that they have individual personalities. Look around on the walls of any transmission shop, and you'll find faded magazine clippings and faxes about the ten different ways an overhaul will turn out -- of the exact same transmission model.

The MT 643 is a far superior transmission -- that much is certain.

Among buses and trucks, engines and transmissions can be swapped almost without limit -- all it takes is the correct bellhousing for the match.

The driveshaft is no problem. Look in the Yellow Pages under Drive Line and Drive Shaft Service. A local such shop can mix and match anything.

Time for another chocolate martini.

[the_experience03]

Well good for you! I like a good challenge too. That might explain why my latest project is a 350 Vortec into a Toyota with a Megasquirt controlling both fuel and Ford EDIS spark. Yep, it's tough, but I'm right there with you...I like a challenge.

I think you're making the right choice with keeping the MT643. Take lots of pictures along the way. I think you'd be the first on the board to have a well documented repower although I'm nearly positive some other members (Frank) have done that and so much more.