Down Hill Descent for Auto

[carlonyc77]

I am finally close to get delivery of my Bronco, a 2.7 auto. I will travel over the rockies to get back home. Question for the forum: in a mountain pass descent, traveling at about 20 to 30 mph on paved road, what gear selection should I use to avoid burning the brakes?
Thank you all

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[Bronc6g22]

2nd should work well. It will be/sound obvious.

 

[BlueWaffle]

Tcase in low, 8th gear, diffs locked, top off and pants down.

 

[SuperDave150]

• It depends. On a lot of things - like your vehicle weight that day, rolling resistance of tires, axle ratio, incline, air density, ambient temperature, and the mood of your passengers.
• Trial and error (Or, guess & check).
• High enough to keep the engine from revving to death, low enough that you only use the brakes lightly & occasionally, such as extra tight corners.

I might tell you that I often use 3rd gear but that’s only in on certain situations. Other times I might say I use 2nd, but that’s only for other situations. Other I times I might say I click it into drive and just enjoy the ride. I might tell you these things, but legal advice tells me not to.

 

[carlonyc77]

In all, shift into manual and pick a gear that won't pull the engine apart right?
I am guessing a rpm range between 2k and 3k?

 

[SuperDave150]

In all, shift into manual and pick a gear that won't pull the engine apart right?
I am guessing a rpm range between 2k and 3k?

Perhaps the engine can sustain a higher RPM than we expect.
I approach it with more of a bias towards brakes. I expect to use the brakes occasionally (such as approaching tight curves) - not constantly, not never - once every few minutes with plenty of cooling time in between.

 

[Brian_B]

The 2.7 may be a touch different, but the 2.3 I don't get to worried about it until I'm starting to push 5k RPM. Which is about the same time I can just start to notice the sewing machine whine over the air/road noise. Now, my wife's Sport with the 3 cyl -- you can't engine brake with that thing at all. But I'd suspect the v6 is better than my i4 at it.

I've got a good several mile 7-8% grade I drive almost every day - 4th on 7MT lets me ride that at decent speed only occasionally touching the brakes. And that's rolling at about 3k RPM or so - so around 55-60MPH. And if the weather is bad I'll roll it in 3rd - RPM is a bit higher but not crazy. Not sure where that puts you on the 10spd.



Just start ticking down gears until you find one that settles pretty well. Not too horrible really.

 

[SuperDave150]

The 2.7 may be a touch different, but the 2.3 I don't get to worried about it until I'm starting to push 5k RPM. Which is about the same time I can just start to notice the sewing machine whine over the air/road noise. Now, my wife's Sport with the 3 cyl -- you can't engine brake with that thing at all. But I'd suspect the v6 is better than my i4 at it.

I've got a good several mile 7-8% grade I drive almost every day - 4th on 7MT lets me ride that at decent speed only occasionally touching the brakes. And that's rolling at about 3k RPM or so - so around 55-60MPH. And if the weather is bad I'll roll it in 3rd - RPM is a bit higher but not crazy. Not sure where that puts you on the 10spd.

Just start ticking down gears until you find one that settles pretty well. Not too horrible really.

When you think about it both engines have strong bottom ends for turbochargIng, and lightweight overhead cam valve train with small valves. So they can probably hold redline without concern - the Nano V6 having even smaller individual components than the I4? But this is all purely hypothetical. I’d still rather be safe than sorry.

BTW @carlonyc77 the computer controlled transmission won‘t let you select a gear that grenades your engine. it will just politely ignore that request because it knows better.

 

[Mjasi3]

Fast land Illinoisan here, going to spend some time in CO and UT this summer... 2.7, 7-auto. When going down a mountain hill, do I switch it Manual, or use the +- button on the shifter knob? Is there difference in the gears it would land in? Will it select the gear I'm currently in? Have never been in mountains before, but know I shouldn't ride the brakes... TIA

 

[Scott R Nelson]

On paved roads I keep shifting to lower gears until it maintains the speed that I want. My goal is always to use the absolute minimum amount of brakes to slow the descent. In 4H or 2H it will be some combination of 2nd, 3rd, and 4th. If I need to use 1st for any amount of time, I really should be in 4L.

Down seriously steep dirt roads, like 10 degrees or steeper, I will use 4L and 2nd or 1st. I've used trail control a few times - that button in the center of the dial - and don't find it to be an improvement over me just controlling it all directly. That mode uses the brakes a bit going down to maintain the specified speed. I feel that it is better to let it speed up or slow down by 1-2 mph without the brakes than have the Bronco use the brakes to stay within 1/2 mph of the selected speed.

 

[Oldhippie]

Just to throw it out there…if ya are driving a brand new bronco home over the mountains ya might not want to rev it too high or get the boost up during “break in”…that being said I don’t much care about “break in” anymore (brakes may be more important to break in properly) and do use manual downshifting with my v6 auto…the ford tune really helped shifting too…pick a gear ya like, lots of options with 10 speeds…

 

[GoHawks63]

Find a good RPM that doesn’t rev the engine too high, especially during the break-in.

There used to be an adage, brakes are cheaper to replace than an engine or transmission.

 

[SuperDave150]

Fast land Illinoisan here, going to spend some time in CO and UT this summer... 2.7, 7-auto. When going down a mountain hill, do I switch it Manual, or use the +- button on the shifter knob? Is there difference in the gears it would land in? Will it select the gear I'm currently in? Have never been in mountains before, but know I shouldn't ride the brakes... TIA

Pull it into Manual, then use the +- button. Then watch the gauge cluster to see what gear it is in.

You can also use the +- button in regular Drive, but in that mode it is taken as merely a light & momentary suggestion; it will revert to fully automatic Drive mode in a few moments.

 

[Mjasi3]

Pull it into Manual, then use the +- button. Then watch the gauge cluster to see what gear it is in.

You can also use the +- button in regular Drive, but in that mode it is taken as merely a light & momentary suggestion; it will revert to fully automatic Drive mode in a few moments.

Thanks for the info. My last truck was a 2015 F150. So absolutely no electronics. The 24 Bronco is a big change. When driving if I switch to M., does it stay in the same gear it was in? I just don’t wanna mess things up.

 

[ksdon]

We have driven Slumgullion Pass in Colorado many times as that area is prime for off road driving.
This is one of the steepest paved passes you will find. Staying off the gas and not caring if someone is behind us, we drive slow. Just an occasional tap on the brake is all we needed.

By keeping the speed controlled on the flat parts we never have seen a need to do more than that occasional tap. The Bronco will gain speed speed but not enough to have brake concerns.

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