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.

[Terryallan]

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.

[Turtle_n_Peeps]

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

[BarneyS]

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

[Dennis_M_M]

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.

[marcsbigfoot20b]

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.

[carringb]

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.

[Weldon]

Diesel without exhaust brake, do not gear down well. I have one and truly wish I had a THE EXH. BRAKE.

[marcsbigfoot20b]

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.

[Terryallan]

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.

[naturist]

Would you rather take 100 miles life off your engine but descend safely or wreck your truck in a corner you can't make because you're brakes faded to oblivion?

It will NOT be even remotely hard on your tranny to travel the entire slope in 2nd, or even first gear. It will put a teeny-tiny-completely unprove-ably greater amount of wear on the engine to do the entire thing in 1st gear.

And frankly, the key here is doing it slowly so the brakes (as much as you have to use them) get lots and lots of time to cool. And preferably cool while the wheels are turning. Cooling while you are stopped on the side of the road, grateful for having survived THAT slope and the last corner, is likely to either burn your brake linings or warp your rotors/drums. If you spend 1 minute on the brakes descending and 5 minutes sitting to cool, you would have been much, much better off taking 3 or 4 minutes descending slowly, but moving the whole time.

My daughter laughs at my son-in-law still over the time he caught his brakes on fire, having used them so hard the disks were glowing red when he stopped beside the road. He'll probably never live it down. And Porsche brake pads and rotors (which he had to replace afterward) are not cheap.

I'd also recommend taking the start of that descent really slow, lest you find out half-way down that you weren't quite slow enough.

[Vannnce]

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

[Terryallan]

an 01 250 with WHAT type of engine? IF it has a diesel with no exhaust brake. even gearing down won't help a lot. IF it has a V10, or other gas engine. Use 1st gear in the really steep part, and you will be fine.
Just start down in 1st. Because it won't shift down at too high a speed.

[coolbreeze01]

Use 1st gear if needed instead of your brakes, won't hurt a thing.

[RCMAN46]

Where is this 16% grade you climbed??

If you have a 4 wheel drive you may consider low range for the 16% part.

[rfryer]

Back in the 60’s when I was young I made my first non tent camping trip with a borrowed, heavy wooden PU with no brakes and I lost my TV brakes coming down Teton pass. I pointed to a small town visible through the trees and told the DW and two sons that’s Jackson Hole, get out and walk down the mountain there and wait for me. I made a hairy decent about 100 yards at a time to try and cool the brakes and survived the experience. But I learned my first lesson the first time out. Don’t pull anything without brakes and use the transmission to control the descent.

Keep your speed down as you start and mainly use the transmission to control it. The speed will increase beyond what you’re comfortable with and then use the brake fairly hard to knock it down maybe 10mph or so below what you want. And repeat as necessary. The object is to minimize the use of the brakes; you do not want to ride them.