Does anybody have the same problem im having, While going down hill the tranny braking shifts down,like it should.But it will still shift down even lower and jump the tach into the red line. Is this a tranny problem and is going into the red area bad on the motor/ service personal told me the red line is just the defueling point.Thanks for any info.
cody

this is covered in detail the owners manual (at least it was in mine) . in the tow haul mode the engine will rev into the dashed "red-line" when used for engine braking. It's called "grade braking" feature. No it won't hurt the engine the engine/drivetrain is designed that way with the allison.

Just wait till you get over 4000rpm's on a downshift!

It will get your attention!

When your foot is off the throttle peddle as in a grade braking situation the RPM's will go higher into the red than when you are accelerating. Completely normal.