Allison "Transmission Brake"?
 

Does the Allison transmission have some kind of retarder in it to slow it down with a load?

Or is it just programmed to downshift more aggressively?

i don't think it has a retarder in it.

I tend to lean towards thinking that the retards are in the truck and not the transmission, personally...

*No Brand Bashing

While my transmission is retarded for sure, I don't believe it has a retarder in it, on it, or around it. It just shifts down when in tow haul, and if my manual buttons worked anymore, you can shift down with those also.

No retarders. The Auto Grade Braking is just a more aggressive downshift programming.

In Tow/Haul mode the converter stays locked during downshifts.

http://www.allisontransmission.com/s...tegoryID=11#84

Trust me, these guys would be retarded no matter what truck they were driving. :ok1:

Not on the LMM+ they have a throttle body that can act as a retard like us and Begle there.:w2::moon: The LLYs and LBZs can have an engine brake tuned into them. I want to think the trans can do something more then just down shift to help slow the truck as well.

Do they use the throttle body or turbo stock as a compression brake? How do you tune it into them?


If the trans does something magic other than downshifting to slow down the truck, that would be what I am most curious about. I don't see how it could retard anything without putting ATF temperatures through the roof...

Magic.:pca1:

:D

The LMM(2007.5) use the throttle body. 2004.5 4500+ (topkick ETC) have the tuning for the engine brake stock IIRC. For the 2004.5 and newer trucks you can tune the Venerable Vain Turbo by closing the vanes to act as a engine brake. Can't do anything for the pre 2004.5 trucks. I don't remember about the trans and I don't think it did much just helped slow the truck a little more. I'll see if I can't fine more info about. Ally run hot anyways over 200* is normal.