Express/Savana Duramax

[Shawn T]

I recently built each of these vans on GMC.com and Chevrolet.com. I was aware that they were going to be available with the DMax but it is "derated". Engine code "LLY" but with only 250 HP and 460 ft-lbs of torque. It also states that it is mated to the 4speed Hydra Matic tranny. Wasn't that tranny replaced with the 4l80e back in 92? It seems like it has been decades since they used the Hydra Matic. Maybe I am wrong. Is it heavier duty than the 4l80e? I guess they could not fit the Allison under the van body. I'm sure they could have used the corny "spacer" between the body and the front bumper like they do on the HD's.

[silverado3500]

The hydramatic 4 speed they are referring to is the 4L80-E/4l85-E. I really don't see why they derate the duramax so much, the 4L80-E is a very strong gearbox.