Risk of down-shifting?

If you have an exhaust brake there would be a separate switch included to turn it on and off. You do not have a Jake brake that's a little different. If you do have an exhaust brake just turn it on and the trans will automatically downshift on its own.

My 2006 Allison 6-speed has a tow/haul mode. If you click into that at the top of a downhill, it will set the speed at which you clicked and will pretty much maintain that speed until you touch the brake pedal or the gas. This works best for me on long freeway downhills.

For narrow winding mountain downhills, I use the tap-shift mode. It sets the highest gear you will allow the transmission to use, which does help in slowing things down. You can downshift with it, but should you?

Cranemec wrote:
Same gear down as same gear up. Downshift before you start down the hill.

That is rather dated, newer turbocharged diesels with high horsepower and low end torque might top the mountain in one of the highest gears, but need a lower gear to do sufficient engine braking. I have personally towed up mountains in 5th or 6th that required 2nd or 3rd on the way down.

Same gear down as same gear up. Downshift before you start down the hill.

Absolutely, you should downshift to get some compression braking out of the engine going downhills
Since you're not familiar with your vehicle yet, consider max rpms when you floor it right before upshift as the max rpms you want to see going downhill before upshifting.

Idk anything about your rig but don't think the exhaust brake is totally automatic so is there no switch for an exh brake?
Do you hear it when decelerating? It's notciable.

The trick is to downshift into the lower gear before you start down the hill. Some say put it into the same gear you would have to downshift to if you were climbing the hill.

WNYBob wrote:
I agree, with using both, but I was told once, ask yourself a question which cost more to fix. So I use my breaks more than the trany.

Ask yourself another question. Which is more expensive. Saving the brakes with the trany. Or smoking the brakes And crashing with a runaway rig? Me. I'll use the trany.

I agree, with using both, but I was told once, ask yourself a question which cost more to fix. So I use my breaks more than the trany.

Paul1944 wrote:
Do I risk damaging my transmission if I down-shift in order to slowdown or to save on my brakes when going down a long and/or steep grade?

Absolutely no problem......IF you anticipate the downhill and down shift BEFORE your speed gets out of control, like at the crest of the hill right after the grade warning sign.
And that applies equally no matter what engine and transmission you have.

The truckers rule of thumb is:
Whatever gear you had to use to pull UP the hill, is the same one you should use going down the other side.

Jake Brake is a name of a product from Jacobs Vehicles and works with your valve train.

You probably have an exhaust brake and its usually labeled engine braked. Mine is by my left hand on the side console with other switches.

As mentioned, the Allison trans wont downshift it means over revving your motor.