Hill Decent Question

[bobsals]

Returning home from our first trip out with the new F-350 6.7 yesterday, and got a surprise I was not sure I was happy with. We have a long hill about 1.5 miles long that we routinely encounter while traveling. Going to camp we hardly knew the hill was there with the power of this new engine going up was not even a slight challenge. However when returning and going down, I thought the engine was going to blow up! The transmission kept downshifting to keep the speed at 60. Tow/Haul was engaged as well as cruise. I was under the impression that the new Ford Diesels had some sort of a mechanism to hold back on the engine sort of a "Jake Brake" feature. Just wondering what other have been experiencing. Am I missing a feature or setting I should be using (Besides the brakes) TX

[steves]

You need to step on the brake to engage the downhill braking . There is not a jake brake but a transmission controlled down shift that helps slow the speed downhill. You can also use your manual down shift feature and on very steep downhill you may also need to brake some. I would not leave the truck in tow mode on a steep downhill.

[1retired06]

X2. You want it to downshift but to lowest needed gear, and by hitting the brake and slowing the truck down, the tow/haul will hold at lower RPM at that speed.

[DQDick]

I don't know about the Ford's, but on the Dodges you have to engage both the tow/haul and the exhaust brake separately. On our truck the exhaust brake is a button hidden in a row of other buttons (seat heaters and coolers etc.) It is next to the tow/haul, which is on the end of the row, but it has to be engaged manually every time you start the truck. I don't like that since I use the exhaust brake most times I drive the truck, but it is what it is.

[Rainer]

The rule of thumb is that you use the same gear going downhill as you went uphill.

That being said, as an owner of a 2012 F-250, you do have to hit the brake when going downhill to engage the speed control, and if it's a really steep hill, you may have to hit the brake more than once. All that makes up for how easy it was to go up the hill with the big new Ford diesel!

[Phil P]

Hi

Ford lists the Exhaust brake as an Option. Check to see of your truck has this option.

If you do have this option Ford’s literature indicates you will have to turn it on. There must be an Engine Brake Selector some where on the dash panel of the truck.

Phil P

[Rainer]

quote:Originally posted by Phil P
Ford lists the Exhaust brake as an Option. Check to see of your truck has this option.

I believe that was on the older engine versions (pre-2011) Ford diesels. Here's the YouTube video from Ford about the engine braking when in the Tow/Haul mode:

http://www.youtube.com/watch?v=tlfz8LAM1xs

[Rainer]

. . .but for DOES have a "Hill Descent Control", but I believe it's for low speeds when in four wheel drive mode:

http://www.youtube.com/watch?feature...&v=TCyCJmPnwDc

[mlh]

Bob your truck has safe guards built in. It is not going to over rev its self in the tow haul mode. You probably can't force it to over rev. The last thing Ford, Dodge or Chevy for that matter wont to do is replace an engine that the tow haul has blown up. Don't worry about it, drive enjoy the truck you are not going to hurt it, Ford wont let you.
Lynwood

[Irlpguy]

quote:

bobsals wrote:

The transmission kept downshifting to keep the speed at 60. Tow/Haul was engaged as well as cruise.

I am not familiar with the Ford "Hill Descent Control" or it's exhaust brake, however I think that on any of the big three the exhaust brake has to be engaged in order to come on. It sure does on my Dodge anyway, and performs great.

I would "NEVER" have my TV in "cruise" when going down any grade, how this effects the operation of the exhaust brake and Hill Descent Control I do not know. Just makes no sense to be in cruise, and might be the reason for what you experienced.

[Carl n Susan]

Listen to mlh, he knows what he is talking about.

On the 6.7L (and the 6.4L and 6.0L diesels) Tow/Haul is standard. I use it anytime the trailer is attached. Tapping the brake will cause a downshift to the next lower gear assuming you are within the allowable RPM range. The Tow/Haul is most effective at higher RPMs (maximum back pressure from the turbo). This translates to maximum effectiveness at 65 MPH in 4th gear, and 48MPH in 3rd gear. While it is scary the first couple of times to hear the engine at 3,000 RPM, there is no real load on the engine and it doesn't hurt it. Should RPMs exceed 4000 due to really steep hill/heavy load and no use of brakes, the computer will up-shift the transmission to save the engine (been there - done that).

I don't normally use Cruise Control in the mountains. But it does automatically downshift the transmission (effectively engaging Tow/Haul) if speed is increasing above the pre-set value.

Having towed a Montana many miles with Ford's various Tow/Haul implementations, I can say it works. You do have to understand its capabilities and limitations. The speeds at which it is most effective, when towing 15K down steep hills, are critical. Plan for those speeds and you can sit back. Otherwise you will have to use the brakes periodically.

On Edit: Corrected gear numbers and Max RPM

[washley1]

quote:Originally posted by steves

You need to step on the brake to engage the downhill braking . There is not a jake brake but a transmission controlled down shift that helps slow the speed downhill. You can also use your manual down shift feature and on very steep downhill you may also need to brake some. I would not leave the truck in tow mode on a steep downhill.

I will strongly disagree with the last sentence! ALWAYS have it in tow/haul if the trailer is on. It is designed to work that way, and in my experience it does.

[steves]

I will strongly disagree with the last sentence! ALWAYS have it in tow/haul if the trailer is on. It is designed to work that way, and in my experience it does.
[/quote]

I agree...I meant to say don't leave the truck in cruise control on a downhill descent. Can I be forgiven?

[bobsals]

Thanks for all the great replies guys. Hearing what you had to say and watching the Ford video on the hill decent, I feel more comfortable now with the process. Some of you have said not to use cruise control while descending a hill. Just curious what the reason is?

[richfaa]

We do not use the cruse and the Tow haul at the same time except on level ground. They seem to work against one another. The cruse tries to maintain the set speed and the TH tries to use the proper gear for the occasion. When going up a good grade it result's in what you experienced. We keep the TH engaged all the time when towing and use the cruse when conditions allow.

You gotta kind of experiment with the TH going down a hill like Steve's said...It works fine even of the steepest downhill grades with minimum braking.

[1retired06]

quote:Originally posted by richfaa

We do not use the cruse and the Tow haul at the same time except on level ground. They seem to work against one another. The cruse tries to maintain the set speed and the TH tries to use the proper gear for the occasion. When going up a good grade it result's in what you experienced. We keep the TH engaged all the time when towing and use the cruse when conditions allow.

You gotta kind of experiment with the TH going down a hill like Steve's said...It works fine even of the steepest downhill grades with minimum braking.

Excellent explanation.

[Rainer]

Having driven two F-250 flavors, 6.0 and 6.7 liter, towing my trailers through 44 of the 50 states over the past seven years, I will sing the praises of Ford's tow/haul and cruise control.

I will admit that on steep descents I have had to take the truck out of cruise control because I did not want to exceed 65mph, the maximum speed rating of ST tires. By applying the brakes the engine senses what is happening and works to slow the the truck and trailer down. And yes, I've had to do this more than once on extremely steep and lengthly descents, most recently leaving Zion National Park into the town of La Verkin, Utah.

[mtheo]

I train firefighters to drive our firetrucks and tanker in the mountains for years. One thing to remenber when staring down hill is you have to use a low enogh gear so that the engine can create enough back pressure to slow down a rig.
That said you have to get in a low enough gear for the engine to create enough braking froce to maintain a slower speed. If the keep over reving your engine, you need to hit the brake to slow the vehicle down and then select a low enough gear to hold back the rig.
Not sure if that explains anythig at all, but I hope so.

[Rainer]

quote:Originally posted by mtheo

I train firefighters to drive our firetrucks and tanker in the mountains for years. One thing to remenber when staring down hill is you have to use a low enogh gear so that the engine can create enough back pressure to slow down a rig.

Are those rigs automatics?

The Ford's automatics downshift automatically.

[bigred715]

On my Chevy, if it is a real steep hill and my RPM's are still really high I will hit the trailer brakes and bring down the speed and RPM's.