Down hill grade

pauly boy wrote:
Relatively new to RVing. My question is while driving down a steep grade road the engine will rev high. Should I gear down? And best way to do this while driving?
Thanks for any help.
Stay Safe...Paul

I read your question carefully... it says "while driving down a steep grade road the engine will rev high." If that is the case, then you ARE gearing down, whether you are doing it manually or the vehicle is doing it on its own. You don't say what year, make and model your RV is. Most newer ones with "tow-haul" mode will downshift automatically on downgrades. Even my VW wagon when on cruise control will downshift to try to maintain a constant speed going down hill.

But like others have said, whether you are downshifting or not you don't want to brake continually on a downgrade.

pauly boy wrote:
Relatively new to RVing. My question is while driving down a steep grade road the engine will rev high. Should I gear down? And best way to do this while driving?
Thanks for any help.
Stay Safe...Paul

If the engine is already revved up then all is working fine.
OK to set your decent speed a bit slower if you do not feel in control.

Actually if the engine is at the higher end of its acceptable range and your speed is still increasing, use the brake pedal long and hard enough to slow down to drop to the next lower gear.

If you have never lost your brakes on a long decent, and most of you have not.

Follow wolfe10's advice. He is spot on.

Get to the lower gear that will hold your speed so you don't have to use the service brake.

Nothing like no brakes going down a very steep grade in Death Valley and the toad braking system is not functioning correctly.

pauly boy wrote:
Relatively new to RVing. My question is while driving down a steep grade road the engine will rev high. Should I gear down? And best way to do this while driving?
Thanks for any help.
Stay Safe...Paul

Buddy, it's just like driving any other vehicle. And re-think your question a bit. But yes, if needed, downshift to help hold speed, within reason.

wolfe10 wrote:

rogerddd wrote:
valhalla360,
What is different about diesel vs. gas? "diesels are a different game"

Gasoline engines use VACUUM (pistons pulling against closed throttle) to generate braking HP.

Diesel engines-- no throttle restriction in intake. So they will have an exhaust brake, VGT turbo that closes and acts similar to an exhaust brake or on larger engines an engine compression brake.

Either gasoline or diesel engines ALONG WITH PROPER GEAR can be used to control speed of descent.

That assumes a newer diesel with exhaust brake or compression brake.

We had an old 7.3 with no exhaust or compression brake...Letting the engine rev helped a little but not nearly as much. You relied on the wheel brakes more and it was more critical to use them appropriately and not let it get away from you. If you let it get up to 75mph and there is a 45mph curve approaching...wheel brakes might not be enough...especially if you already heated up the brakes.

I learned this lesson by experience with a Hill too long and steep decades ago
http://www.explorenorth.com/library/roads/bella_coola_hill.html

We had a 1992 3/4 ton GM van pulling a tent trailer. I started down in 2nd gear, using the brakes on each switchback curve. My daughter had her window open and said there was a burning smell. I stopped and found there was indeed a hot smell from the wheels. A few minutes later I bravely proceeded in low gear and soon came to a rest stop where I could safely park. There was a melted car there. The aluminum engine had the shape of a puddle on the ground. After a good rest to cool down we proceeded down in low gear. A good lesson!

I don't use the tow/haul mode going down hills any more. I find that if I am using it and begin going too fast, briefly stepping on the break brings me to the next lower gear at an RPM I don't feel comfortable with. If the hill is 6 degrees for a couple miles I manually slow way down at the apex and gear down manually. Then if I feel the speed increasing too much, I tap on the brake to slow the vehicle down.

^6 deg is steep. Not something you'll find on most highways, but you may mean 6%.
Either way, yes some newer tow haul programming on a lot of vehicles have quite aggressive downshift profiles.
But you don't need to worry, it's not hurting anything.

Really doesn't matter HOW you get to the correct gear to hold your speed in equilibrium. This can vary by make, model and year of chassis/vehicle.

The important this in that you DO!