Need advice for towing downhill....

[CMunrock]

Hello, I pulled me 30' fifth wheel up a 10 mile grade with 6-16% slopes. Like a cat that climbed the tree, I'm wondering the best way to get down. My trruck is an '01 F250 with an auto tranny. To keep it in control, is it best to shift way down or rely on the brakes. I'll take breaks to let everything cool, but is it pretty hard on the tranny to keep me slowed down? Any time tested advice is appreciated.

[edm3rd]

One last minor point, have air conditioning on when downhill, adds a small amount of additional drag. On uphill, if uncomfortable with engine temp rising, roll down the windows, and turn the heater on. Don't expect miracles, but every bit helps. The a/c downhill adds up to half a gear.

[CMunrock]

Thanks everyone--a lot of great responses and advice that I followed and we made it down with ease. This is hands down one of the most useful forums I've ever used.

[time2roll]

I need to completely stop to go in or out of 4lo. Not going to happen at every curve.

Have been a few roads where I have thought if it was unpaved it would have been easier. I would convert my front hubs if there was an easy kit.

[Tystevens]

RCMAN46 wrote:
I have used 4 wheel drive on pavement as long as the distance is short and the speed is less than 20 mph.

Well, it is no problem using 4 low on pavement as long as the road is relatively straight. It is the sharper turns that will cause problems for you.

[Bedlam]

One of the reasons I have manually locking hubs is so I can run low range on dry pavement. A steep hill has nothing on the high ratios you produce in low. If it is on snow or a loose surface, that should be another thread.

Reader1: My DW also panics when she sees a guard rail with a drop.

[RCMAN46]

I have used 4 wheel drive on pavement as long as the distance is short and the speed is less than 20 mph.

Better than overheating the brakes. Do not forget a 16% grade is very steep and I would think you would want the speed to be less than 20 mph anyway.

[Reader1]

Lots of good advice on a difficult subject. You have really hit on the technical aspects. But...if your wife is a nervous passenger like I am, my advice for her is to close her eyes, read a book, play a game. I can't help him drive but I can and have added to his stress, so I try to keep busy.

[time2roll]

Slow up before the curves. As you exit the curve do not be tempted to touch the throttle. Just let it coast back up to speed.

[Tystevens]

My '06 Duramax had plenty of engine braking -- seemed on par with the gas engines I've owned.

And to the OP, your brakes would be long gone after 10 miles of steep descents! Gear down. Is this on a gravel or dirt road? When we're getting far off the paved path, we often use 4-low to come down the steeper grades. Works like a charm -- never have to even touch the brakes. You wouldn't want to do it on paved roads, however.

[coolbreeze01]

Been up and down the back grade many times. Low gear is best in the steep spots. Enjoy the ride.

[CMunrock]

The road was hwy 18 going into Big Bear Lake, California. The engine did great going up, but the tranny got warm, which is why I was wondering if it would do the same thing if used to slow the truck on the descent. Thanks everyone, for the replies--very helpful.

[blt2ski]

Must be a 6.5td thing, my 5 spd was great for going down hills, put it in a lower gear, would stay at a slow speed. The 454/th400, now those two were horrible for going down hills. My 92 IHC with a idi7.3 and an emanual 7 sp does just fine going down 20+% grade which I have done a few times locally here in the seattle area. 15-20% grade are not that uncommon. 6% is a yawn, someone is complaining about this grade?

Also, the use the gear you went up in......not so sure that works these days, as so many rigs have more than ample HP to go up hills that we used to go up at half or 3/4 of the speed. SO choosing a gear or two lower than you went up might be a better thought pattern.

marty

[time2roll]

To the OP: 6% and 16% are very different. 6% is not much effort besides going slower and use lower gear. 10% plus needs extra caution of going extra slow and using the brakes effectively. To be effective use them moderately firm to slow 10 to 20 mph below the speed limit before you coast back up to speed then repeat. This braking applies proportionate braking force to heat ALL the drums and rotors, then coasting a bit cools them. Don't just lightly ride the brakes as this will tend to overheat one axle and letting the rest be ineffective. If gas downshift to get RPM up around 3500/4000. If you have a diesel I will leave that to the others.

[Turtle_n_Peeps]

I'll YouTube my 6.5 if you want?

No tricks or anything like that. I will bring it up to 60 MPH and then downshift. If you are correct it should take a very long time with NO engine braking.

If I'm correct the speed will come down very quickly just like it has in my 10's of thousands of miles of towing.