Have a friend who is tech at local Chevy dealer. He tells me that another of the techs who is the trans specialist at the dealership just got back from a refresher course at GM tech school.


Said that instructor mentioned off the record that it only took a few parts in the trans and some electronc work to convert our Allisons to 6 speed, sort of a double OD. This would be great on long, flat high speed interstate runs.


Anybody else heard anything on this?

Yep I've heard that also. Will also need a software change to control the shifts/downshifts etc. There are 6 speed Allisons in some bus motorhomes.


I assumed aftermarket companies would tackle this someday.

The way I understand it, the extra gear is a lower 1st. It is used in heavier applications like the medium duty trucks for taking off with big loads. Super Diesel

Hmmmm...


The way it was discussed quite some time ago over at the "page" was that the 6th gear would be a 0.61:1 ratio to go with the 0.71:1 ratio our 5th gear currently has.


75+ mph at 2K or less RPMs sure would be nice for mileage running empty on the highway. http://www.dieselplace.com/forum/smileys/Cool.gif

Anything further on this? I am really interested...

My son-in-law works at Allison and is currently working on this project. I will be a higher final drive ratio and will be out in 06 models. What a job to have when you get paid to try and break things.








Greg