Risk of down-shifting?

[Paul1944]

I have a 2004 Coachmen Sportscoach with a 330hp CAT, and 6-speed Allison transmission. Here is my question. 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? In reading through all my manuals I cannot determine if my coach is equipped with a jake brake.

[Grit_dog]

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.

[schlep1967]

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.

[Terryallan]

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.

[WNYBob]

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.

[Sam_Spade]

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.

[Big_Katuna]

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.

[Jim-Linda]

Research exhaust brakes, not jake for your engine.

[jim1521]

Most transmissions will protect themselves, so you'll need to use both brakes and transmission. Get RPMs down to the lowest gear that will allow control, then use brakes to help drop RPMs. Don't ride the brakes (or do your best not to). Work your way down until you get to your desirable speed. Use lower gears as much as possible.

[12th_Man_Fan]

The Allison transmissions I am familiar with will not allow you to downshift if the RPMS are too high. It has it's own computer to prevent damage.

If you try to downshift at too high RPms the tranny will not shift.