New to the forum, I have a 2003 Silverado HD Duramax with Allison Transmission. This year we started to pull a 26ft 5th Wheel. Having a problem with control speed down hill even with the towing on. When I brake hard the transmission will gear down and the RPM's will go in the red. What I'm doing wrong?

 

let it go use the brakes lightly, you'll be fine in the red a little bit

 

Your allison is trying to assist in speed control. I have this happen now and again. I limit the issue by slowing my rig down as quickiy as possible to the speed I want or just under the trans will normally only shift down to 4th around 3,000rpm which if fine and out of the red.

 

Trailer brakes ?

 

my thoughts exactly

 

Trailer brakes and a brake ast will go along way for your trans brakes and wear