Use the stabbing method to slow the truck on those downhills to preserve the brakes.


Stabbing is just a hard braking event to slow it about 5 mph then let off to cool the brakes.


Follow the suggested speed that is posted for trucks on the downhill run. That is a good starting point.

 

Yes, it will. Here's the "however" part - with enough mass (large truck and camper) and a steep enough grade, even locking the transmission in first gear may not be enough to keep the speed down (in theory). In other words, at some point you are going to encounter a grade that is going to be more than cruise or manual can comfortably handle, and you are going to have to step on the brake. This will, of course, disable cruise, and you will suddenly find yourself in sixth gear being pushed down the mountain by your trailer.
Best practice is to limit the transmission by locking out the upper gears (or use manual mode) and judiciously applying the brakes to manage your speed on the grade.

 

The combination of 6 speed, manual mode, tow haul and gear lockout gives the driver many combinations when hauling loads. I use them all at different times on our journeys depending on road conditions, I also use the CC more on this truck than any other truck I have ever pulled with because of this combination, you just have to try them all to see what works the best for the roads and what your comfortable with. I've pulled for years and with this truck with the 6 speed and drive by wire it was a long learning curve to figure out what worked for me.

Denny

 

That is EXACTLY what I do. Use Manual Mode folks. You'll never want to tow heavy without it again. Denny turned me on to using the mode last summer. And trying it for myself made a firm believer out of me.

And the heavy braking then off again method is what I was taught in truck driver school 30+ years ago. Also going down a grade in the same gear you would be going up the equivalent grade in. Start at the top of the hill in the gear you want to be in while going down the hill. Not quite as critical with today's auto transmissions, but a good mind set to have.

 

My 6.0 with automatic holds going down steep grades very well in Tow/Haul. If it starts going too fast, I just hit the brake and it shifts down automatically. Or as an alternate I can put it in cruise control and select the speed - 40 - 45 whatever. Both works very well!

 

When in tow haul mode, mine will down shift on down grades to maintain the same rate of speed I am traveling, as long as the speed I was going before letting off the accelerator after cresting the top of the hill and heading down the grade, is at or less than the desired down grade speed. An exception is, if it is a very steep grade, and the rpms rise to an unsafe engine speed, your truck will upshift to a safer engine speed for the health of the engine. I will use my brake to assist the tow haul system to keep from engine overspeed. Tow haul can't do all of the work, however. The tow haul does help me save my brakes to its capacity.

 

I don't care much for the Tow/Haul functions shifting to engine scream pain though do use it and often shut it off on long steep downhills, relying on the M position or at least shifting down manually using the paddle switch and occasional braking to maintain safe, comfortable speed. I also manually shifted as much as possible on the last truck too, a 6.8 V10 to prevent those 4500-5000 rpm engine wails. This method has carted us in the sig 5er through the Adirondacks, Berkshires, Green, Rockies, Wasatch and Allegheny mountain ranges, just to name a few, with up to 8%, 5+ mile grades. I seldom rely solely on trailer brakes as they are at best, mediocre, being really too light duty, IMHO, in the drum brake configuration for the weight they are expected to whoa down.

 

Remember, v-8 diesel engines (even more so v-10s gassers for that matter) are designed to run at higher RPMs. In fact, that is where their optimal power bands are. 6 Cyl diesels are different, enjoying lower revs with gobs of power at lower RPMs. I have to remember this when I drive bigger diesel trucks at work, to keep RPMs down. My 6.0 likes to rev a bit more. Don't let RPMs scare you while your driving a Ford or Chevy diesel light duty pickup.

 

The 6.8L V-10 is perfectly content with engine braking at 4500 - 5000 rpm on steep downhill grades. That is exactly what it was designed for, and it will do it all day long. I would never dream of shutting off the Tow/Haul function on a steep downhill grade.

 

rpm's under power or as engine braking.....

there is the Human issue... and AGE..... Comfort....

till I passed 55... 12,000 rpm motorcycles 1,000 cc, 4 cylinder engines.. I loved and lived with..
or 8,000 rpm V8 car engines...

now at 65.... 7,000 is my limit of comfort....

as for my Ford 6.2L.. I fully understand it limits... but 5,000 rpm during engine braking is not pleasant to my nerves or ears..
I know it will do no harm to itself.. but to me.. not fun.

So I understand... DON'T Get OLD..... its' a Trap...
.
.ever hear the 125cc 6 cylinder 4 stroke, Honda racing engine.. red line was 22,000 rpm's.
.

 

WOW... that gotta be a screamer ! And prob no muffler either...

 

For some reason, this post reminds me of an old girl friend.

 

There are many different modes and ways to use all the tow features on these trucks. I find the engine brake (what Ford calls it) pretty effective. My goal is to stay off the brakes and keep trans shifts to a minimum and it works quite well for me. Now if it is in automatic mode, it will downshift whenever you hit the brakes and then it gets a little clumsy with delayed upshifting at the bottom of the hill. I tow quite a bit in mountains and my preferred method is with the trans in manual mode. Then I use the first push of the engine brake (automatic I think). Full control of gearing and no annoying downshifting, revving, and delayed shifts when you get back on the go pedal. I don't think anybody mentioned it but you will notice a little boost on the gauge when it is working, up to 10 lbs in my experience.