Chevy 8.1L/Allison combo

Yes it does and happens to me when tapping the brakes while going downhill too.

This is what the Allison transmission was designed to do when in Tow/Haul

Yes, in T/H mode it will down shift for you when you step on the brakes.
Do you have a manual for the truck? It should describe the feature in detail. I use T/H a lot even when not towing just for this feature, it saves on brake pads. My factory rear pads last 185,000 miles, the front pads a bit longer.

Absolutely it downshifts. It's certainly different than a 1500. It makes you think you'
re driving a real truck!

Thanks everyone.
Don't have the truck yet, so just wanted to clarify if that feature was there.
Having a hard think about grabbing one.

Actually taping the brake doesn't cause it to immediately downshift. What it does is keep the truck at the speed you were traveling at the time you hit the brakes by downshifting when needed and not just one time. I saw rpms as high as 4500 coming down some mountain roads with my 02 8.1/Ally

hornet28 wrote:
Actually taping the brake doesn't cause it to immediately downshift. What it does is keep the truck at the speed you were traveling at the time you hit the brakes by downshifting when needed and not just one time. I saw rpms as high as 4500 coming down some mountain roads with my 02 8.1/Ally

You’re both right. If I tap the brakes when the RPM’s are low, it will nearly immediately downshift. It knows and/or quickly senses the increase in RPM when you lift back off the pedal. Also if you just hold the pedal without decreasing speed, it downshifts to help out. It’s possbile different years have different programming too.

An increase in speed is what causes the downshift not an increase in rpm

hornet28 wrote:
An increase in speed is what causes the downshift not an increase in rpm

You’re right. My brain said RPM since that’s what I associate with the engine noise as a truck speeds up downhill. With the torque converter locked they’re one in the same anyway.

I feel why let the rpm's get to 4500 or even 4000. To me going slower at the top of the incline is the answer. Only because I feel this way the engineer's have figured the trannie will not hurt the engine. I have had to hit the brakes a couple of times to downshift on our 2001 8.1 or even on the 05 duramax. Nice feature that all can do because of the Allison.

chevman