engine brake while towing?

wilber1 wrote:

ShinerBock wrote:

coolbreeze01 wrote:
Actually, the shifts aren't firmer up-shifting in TH

Actually yes they are.

Only because RPM is higher and more throttle is being used when the shift occurs. If more torque is being applied to the clutches when the shift occurs, of course the shifts will feel firmer. Any automatic transmission will do that.

My manual says that in tow haul.

"Fourth to fifth upshifts are delayed. Shifts into fifth and sixth gear are still allowed under steady cruise conditions. Closed throttle downshifts (for improved engine braking) may occur during steady braking maneuvers."

That is where the problem is with my truck, it is too aggressive on the closed throttle downshifts. I will be descending a hill with EB and TH on and it will downshift when I don't want it to, forcing me to either add throttle or turn TH off and upshift to maintain the speed I want. I find it easier to just turn it off beforehand then re-engage it when I reach the bottom of the grade. Later trucks may operate differently but I do not like the way tow haul and the exhaust brake work together when towing with mine. It's a programming issue, not a mechanical one. Ironically, they work better together when not towing.

Try using your cruise control next time out, just set it at the speed you want to maintain. I think a lot of people feel weird about using the CC going down a steep grade but it works, it seems to pull together the operation of the trans shifting and the exhaust brake. I think it is because the truck computer has a target speed, otherwise the truck is looking at amount and length of brake apply. If you apply too long or are aggressive on the brakes it starts applying too much exhaust brake and down shifting, then you need to add throttle to not slow down too much. On most of our trips the cruise is on most of the time except in heavy traffic, I just use the speed up and down. I have noticed my trans does not get as hot.