Need advice for towing downhill....

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.

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

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.

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.

marcsbigfoot20b27 wrote:

Terryallan wrote:

Vannnce wrote:
Why do you say if its a diesel gearing down wont help? Down shifting my diesel holds me way better than any gas truck ever has. I can go down a 6% grade and simply pulling it out of overdrive or down to second will maintain my speed with my fifth wheel

If it does as you say. then it has some sort of after market exhaust, or engine brake or trany brake. diesels by design little to no engine braking in their natural state. Why? Because while they have tons of compression on the front side. All they have on the back side is a great big open hole. Nothing to create back pressure.

That is why Exhaust brakes were invented in the first place. To give engine braking to diesels, because they didn't have any. Having driven the big trucks. I learned the hard way. Diesels in their natural state, free wheel down the mountain, in any gear.

What are you talking about????
Diesels have so much compression that they like having 2 batteries to start them. Plus there is no throttle plate, so they are always sucking in as much air and compressing it if your foot is on or off the pedal causing enging braking.
Automatics are designed to freewheel or up shift when you let off the gas pedal in normal city driving so you dont feel the engine braking in top gear. Put one in 3rd or any manual gear in the city and cruise steady then let off the pedal, make sure you have your mouthpiece in before you bite the steering wheel.

The diesel I drove was not an auto. It was 13 speed Fuller road ranger. No engine braking.

Again guys. Exhaust brakes,,, AKA Jake Brakes were invented to give diesels braking, because they have NONE. IF, as many of you claim. Diesels have lots of engine braking. There would be no need for Exhaust brakes.

My 6.5 diesel with a 4L80E no EB or TH brakes way better than my gas 350/T400 ever did.

marcsbigfoot20b27 wrote:
Car has average 9.5 to 1 compression ratio.
Diesels more like 17 to 1 and there is not throttle plate.

I have driven my friends F250 7.3 PSD with a manual 5 speed and if you got it up to 2500 rpms in 1st 2nd or 3rd and let off the gas pedal you would snap your neck.

Then your friends F250 has had an aftermarket exhaust brake installed and the lack of a throttle plate is the reason there is no compression braking on a diesel. There is nothing to restrict the movement of the air through the engine!

Mine will do that too if my exhaust brake is activated. I have an F250 with the 7.3 PSD and can tell you there is no compression braking on downhill, in town, or any other time other than a small bit - certainly not enough to hold back on a hill or mountain or to cause any neck pain! :B
Barney

SLOWLY. Pick your speed, pick a gear that matches that speed. As you descend let speed build gradually to about 5 MPH above your target speed, brake FIRMLY to get about 5 MPH below your target speed and then get your foot off the brakes. Repeat as needed, DO NOT RIDE THE BRAKES! Allow the brakes to cool between applications.

Do it that way and you will have no problems. Just go down slower than you went up and in the same gear or a lower one.

Car has average 9.5 to 1 compression ratio.
Diesels more like 17 to 1 and there is not throttle plate.

I have driven my friends F250 7.3 PSD with a manual 5 speed and if you got it up to 2500 rpms in 1st 2nd or 3rd and let off the gas pedal you would snap your neck.

marcsbigfoot20b27 wrote:

What are you talking about????
Diesels have so much compression that they like having 2 batteries to start them.

Nope. Without an EB diesels have barely engine braking. Diesels have dual starting batteries because of the draw from the glow plugs or intake grid.