:help:


03 LS ext cab. using Hypertech Power Programmer in stage 1 program pulling 15,000 lb. plus/minus. In Tow mode with OD locked out the engine breaking is supposed to control downhill speed. It does that but with too much agression. At 45 MPH the allison will downshift to 2nd gear and the engine speed almost pegs out "4500 rpm". Had to select Neutral and free wheel down the 5% to 6 % grade. How can i avoid this from happening?

completely normal. No reason to try and correct what is normal. 4500 on a downshift is actually with in 'safe' zone.

Yup what Eric said. It freaked me out the first time too. I love the way it sounds too.

rturnrvn, when you get to your comfort zone give it just enough throttle to hold the speed in the gear you want. With a little practice you can keep the shift RPM anywhere you want them. The longer/harder to push on the brakes coming down a long hill the more aggressive the down shifts. If the Allison pulls you down too much get on the throttle for short burst. It will up shift a gear to let you start over. I have to push down about half way to mine to up shift. Later! Frank

ditto

I waited for parts to start coming out from under the truck.

didn't happen, and now I'm about 25,000 miles of towing into it, and don't worry.

If you are that concerned, as I was, put on an exhaust brake.

You will find yourself giving it throttle because the EB will really slow you down.

Happy towin............

Thank all of you for your input. Think i have got a handle on this now. Happy motoring to all of you.
Jerry

i was scared when mine went to 3100 rpms, if i hit 4500 i would have really freaked, I guess now i know, but ill still get scared.

Yeah that happened to me coming down the questa grade into SLO on my way to pismo right after I got the truck........I was waiting to toss somthing out from under the truck.....

You are pulling the trailer weights that I am pulling. The only safe way to handle any % grade is with an exhaust brake. I had a friend that lost his trailer brakes going down a % grade hill and almost lost his life. Play it safe, get an exhaust brake...I would recommend B-D Exhaust Brakes.

would like exhuast brake...but heard no can do with lly, anyone know if true?

i heard the same. no exhaust brake on the duramax. I dont know about lly vs lb7. All I heard was that the exhaust brake causes a build up of pressure somewhere, I dont even know where, and as a result that something that the pressure builds in will crack open and you will be SOL. So who knows where the pressure is building and what is cracking? Id like to know so that next time I put my two cents into a question like this I dont sound like a total ass. On the positive side, at least Im consistent.

would like exhuast brake...but heard no can do with lly, anyone know if true?
Have been told that BD is the only EB that works with the A'lly. Dont have one yet but will probably add at some time. Dont get into that many steep grades, but when i do i sure would feel better knowing i can maintain my downhill speed.
Jerry
:grd: