First time towing in mountains

[rodigio]

2019 Ford F-350 XL gas v8 towing 8000 lb toy hauler. I was going down Daniels canyon towards Heber, Utah, about a 6 to 8% grade, tow/haul was on and transmission was in drive. Suddenly the truck downshifted by it self into 2nd gear, sending the rpms to over 5000 and startling the heck out of me and wife. We maintained about 50 to 55 mph down the canyon using no brakes and I could not get it to upshift even when I accelerated. When we got towards the bottom of the canyon the truck upshifted itself and drove normal the rest of the way home to Salt Lake City.
Wondering if this is normal, and what I can or should do differently next time.

[dalford]

Were you using cruise control?

[rodigio]

No, I wasn't using cruise control. Thanks.

[dalford]

I have a diesel F350 and for me when in tow/haul when i apply the brakes the engine will downshift a gear and then another gear when I apply them again. Did you apply any brake?

[rodigio]

I hit the brakes once when we started the descent but that was it.

[dalford]

Is over 5000 rpm above redline for your truck? If no, then that is ok.

Did you try turning off tow/haul to disengage the transmission? If no, try that next time.

I have exhaust brakes on the diesel. I usually go downhill using cruise control. I set the cruise speed pretty low as the truck will speed up above the set cruise speed before the tow/haul breaking sets in. The sped will slow and hold to the cruise speed and if I feel is too slow I will bump up the speed with the + button.

[dalford]

Originally Posted by rodigio

I hit the brakes once when we started the descent but that was it.

That probably set the downshift into place. Seems a little drastic though to jump all the way to 2nd gear.

Maybe next time start downh a little slower?

I know what you mean about trying to get the tow/haul to let go of the tranny. Try turning off the tow/haul and then re-engaging it.

[007matman]

Totally normal for tow/haul mode. The trans shifted down and used the engine to slow your descent. Tapping on the brakes is probably what started it. Giving it a little gas will pop it out or shift out of tow/haul mode.

[whj469]

My 2019 F350 diesel has had a recall to reprogram the transmission. Have you checked to see if yours is included in the recall?

[Miweber929]

It’s normal, most trucks nowadays use engine braking on steep grades to help you maintain speed and control.

[bubbles]

Originally Posted by rodigio

2019 Ford F-350 XL gas v8 towing 8000 lb toy hauler. I was going down Daniels canyon towards Heber, Utah, about a 6 to 8% grade, tow/haul was on and transmission was in drive. Suddenly the truck downshifted by it self into 2nd gear, sending the rpms to over 5000 and startling the heck out of me and wife. We maintained about 50 to 55 mph down the canyon using no brakes and I could not get it to upshift even when I accelerated. When we got towards the bottom of the canyon the truck upshifted itself and drove normal the rest of the way home to Salt Lake City.
Wondering if this is normal, and what I can or should do differently next time.

Sounds like your tow/haul mode is working.

[5picker]

Originally Posted by 007matman

Totally normal for tow/haul mode. The trans shifted down and used the engine to slow your descent. Tapping on the brakes is probably what started it. Giving it a little gas will pop it out or shift out of tow/haul mode.

Originally Posted by Miweber929

It’s normal, most trucks nowadays use engine braking on steep grades to help you maintain speed and control.

Originally Posted by bubbles

Sounds like your tow/haul mode is working.

Correct.

Tow/Haul working as it should.

I live in the mountains of PA and encounter long 7-11% grades often.
It isn't uncommon for my transmission to downshift into 2nd gear.

The computer won't let the engine rev too high to cause any damage.
Let it 'sing' and enjoy the benefits of engine braking.

I often find at the bottom of a long decent I have to give it a good bit of throttle to get it to upshift, even if I turn tow/haul off.

I often use the 'manual' switch on the gearshift lever and do the downshifting myself. The computer 'learns' as you drive but I can often do a better job depending on terrain.

[Flybob]

Found that if your tap the brakes periodically on steep grades, the downshifts are more gradual and more effective.

[NMWildcat]

I hear ya. I also hate the extreme downshift and resulting rpms. I don't care if the computer is controlling things correctly and won't hurt the drivetrain.
So I start downhill slow, shift to manual, and select the appropriate gear to maintain the speed I want to go. Then, if speed increases, I tap the brakes and perhaps select a lower gear. Get to the bottom and shift back to drive.
Works for me, and we have been over most of the major mountain passes in the country. Same truck
Of course, you get the folks who are in hurry to go nowhere, honking behind you and continually peeking and trying to go around. I will pull over if possible, but I always wave at them, usually with all my fingers........

[HangDiver]

Originally Posted by NMWildcat

I hear ya. I also hate the extreme downshift and resulting rpms. I don't care if the computer is controlling things correctly and won't hurt the drivetrain.
So I start downhill slow, shift to manual, and select the appropriate gear to maintain the speed I want to go. Then, if speed increases, I tap the brakes and perhaps select a lower gear. Get to the bottom and shift back to drive.

This is exactly what I do. I do use tow haul mode in drive but manually shift into the gear that I want to use while descending in steep terrain.

[67L48]

Normal. Tow/haul is pretty good at reacting to grade, speed, etc. The downshift is part of the process.

Fords, at least, also hang on pretty hard to that low gear. You sometimes have to ride it hard for a period of time before the truck believes you that engine braking is no longer needed ... and then it will finally upshift. Others toggle the tow/haul mode off and on to facilitate the truck letting go of the low gear (2nd or 3rd, usually).

Good luck.

[Herk7769]

Originally Posted by 007matman

Totally normal for tow/haul mode. The trans shifted down and used the engine to slow your descent. Tapping on the brakes is probably what started it. Giving it a little gas will pop it out or shift out of tow/haul mode.

Ditto

Tow Haul mode selects the optimum gear for the load on the transmission.

The brake tap and the trailer's "push" was what triggered the downshift to that gear.

[Wheelman]

Totally normal - working the way the engineers designed it. Scared the daylights out of me and my wife the first time it kicked in on my F250 Super Duty.

[hankpac]

Your truck acted normally for conditions. Your question is “what can (or should) I do differently?”

Most people fail to slow at the crest of a climb. I always slow down or at least let off at the crest and let momentum carry me over and the hill crest slow me down, so that when the down-shift occurs, the engine will not over-rev. Even if not redline, suddenly dropping to second gear at 65 is alarming and unnecessary.
Slow to a speed that has your engine reving comfortably, and get into the slow lane. Turn on your flashers if that is 45 or less. The slower speed is designed to save your brakes in case you need an emergency stop (blowout,etc). It is also designed to save your brakes so you still have them at the bottom. There is no more terrible feeling than to push the brake full on and get absolutely no braking sensation at all.
If your engine is reving loudly you have not slowed enough.

[rlh1957]

For a gasser 5000 rpm isn't bad for the engine. what is redline 6000, 6500? In tow mode it will downshift to go up a grade and downshift as well using the engine as a brake to help save trailer and TV brakes. You can easily burn up the brakes with a slight drag down a ill. Diesels have an exhaust brake in addition to the tow mode that helps. My wife 'insisted!' we get a diesel because she didn't like the high rpm's of gasser and lower torque going up and down hills in our Titan!