Ford hill descent control - is it bad?

[SageRpod]

I have been using the Hill Descent Control on our F150 while coming down steep inclines. Everything I have read is that this is a good thing whether or not towing. This weekend a fellow in the same campground, towing a tandem axel Airstream with a F150 Platinum was telling me he was told by the dealer not to use it while towing because it would ruin the 10 speed tranny and brakes. I find this really hard to believe since you'd be using the tranny and brakes anyway and the HDC also incorporates traction control (but I'm not sure how). So he had me second guessing myself, but again, I cannot find anything out there that indicates not to use it while towing.

I know we have some knowledgeable F150 drivers on the forum. I'd like to hear your thoughts on using Hill Descent Control while towing.

Thanks

[YakRV]

Although I am an F-150 driver, I’m not sure how “knowledgeable” I am - especially with towing - but here are my thoughts. If you’re talking about using HDC for an off-road, rough terrain incline, that’s what it’s made to use for. Have at it.

If you’re talking about towing on steep grades in a highway environment, I’m not so sure about that. We have Adaptive Cruise Control, and I use it in those situations to very successful effect. The truck maintains a steady speed at the setting I choose (and that I can adjust very quickly on the fly). The F-150 selects the proper gear and controls the braking so this - very novice driver with towing a trailer - doesn’t screw it up.

I know others might swallow their chewing gum with how I ride, but it works perfectly well for me and I’m quite comfortable doing it. As always, YMMV.

[SageRpod]

Thanks YakRV. I’m talking steep, paved incline around 15mph with tight corners.

[splitting_lanes]

A quick google search returns information from Ford that says Hill descent control is for speed control while towing and going downhill.

Edit: the dealership won’t make money as often on brake service if you use it.

[TTMartin]

Originally Posted by SageRpod

I'd like to hear your thoughts on using Hill Descent Control while towing.

How is that different than Ford's Tow Haul Mode?

[Centex]

FYI / FWIW, attached is the complete text relating to Hill Descent Control from the 2022 F150 Owners Manual (the 2-page topic-specific section and a later mention in the driving hints section).

I've never used the feature, towing or otherwise, so for me an interesting read .... note the effective speed-range limitations (2-20 MPH), the self-protection relating to heat (likely to protect the tranny), etc.

Word searching the entire manual I find no reference to use / non-use of Hill Descent Control in the towing sections.
____________

I've also attached the text describing HDC operation from the 2022 F150 Workshop (Service) Manual, likely more than you want to know, but there it is.

Have Fun!

[JeffinBC]

Originally Posted by TTMartin

How is that different than Ford's Tow Haul Mode?

Tow/Haul mode is purely transmission related (no braking involved) and isn't speed limited. Shift points are adjusted to keep the engine in the power band and 9th and 10th gears are typically locked out... or rarely come into play while towing in my experience. The engine/transmission combo will also do its best to hold a particular speed on downhill grades by engine braking. If you have a 2.7 or 3.5, the engine braking is not as effective as with a larger engine like a 7.3 V8 or diesel. Hope that helps. Someone will correct me if I've missed something or was incorrect. Take care.

[John in Santa Cruz]

Originally Posted by JeffinBC

... the engine braking is not as effective as with a larger engine like a 7.3 V8 or diesel. ...

diesels don't have a throttle body so they don't actually have that much engine braking, unless they have a 'jake brake'... diesels control the engine acceleration by how much fuel they inject.

[Ron in BC]

Originally Posted by JeffinBC

Tow/Haul mode is purely transmission related (no braking involved) and isn't speed limited. Shift points are adjusted to keep the engine in the power band and 9th and 10th gears are typically locked out... or rarely come into play while towing in my experience. The engine/transmission combo will also do its best to hold a particular speed on downhill grades by engine braking. If you have a 2.7 or 3.5, the engine braking is not as effective as with a larger engine like a 7.3 V8 or diesel. Hope that helps. Someone will correct me if I've missed something or was incorrect. Take care.

I find the braking quite effective with the 2.7 and it's useful. Sometimes I have to use the brakes to keep the revs to a reasonable level. Don't like how it stays in a lower gear even after you've started pushing on the gas pedal.

I often use the manual gear select instead.

Ron

[SageRpod]

Well, I'm going to continue to use the Hill Descent Control feature. I have yet to find a any evidence through Google searches that indicates it is a bad idea while towing. Not going to worry about what the Airstream traveler said. From what I have read, the HDC has built in protection to prevent damage and I am going to trust that works as advertised. Everything else on the truck has worked as expected, I have no reason to doubt the HDC won't work as well.

[Brian B-P]

Originally Posted by John in Santa Cruz

diesels don't have a throttle body so they don't actually have that much engine braking, unless they have a 'jake brake'... diesels control the engine acceleration by how much fuel they inject.

Yes, a diesel needs a compression-release brake (a.k.a. "Jake brake") or an exhaust throttle valve to produce useful engine braking. A variable-geometry turbocharger can be used as an exhaust throttle, to some extent. Compression-release is more effective but noisy and not smoothly controlled.

[WillyB]

This Ford article seems to indicate Hill Decent for trailering.

https://www.ford.com/support/how-tos/ford-technology/driver-assist-features/hill-descent-control/

[MrLynn]

Originally Posted by JeffinBC

Tow/Haul mode is purely transmission related (no braking involved) and isn't speed limited. Shift points are adjusted to keep the engine in the power band and 9th and 10th gears are typically locked out... or rarely come into play while towing in my experience. The engine/transmission combo will also do its best to hold a particular speed on downhill grades by engine braking. If you have a 2.7 or 3.5, the engine braking is not as effective as with a larger engine like a 7.3 V8 or diesel. Hope that helps. Someone will correct me if I've missed something or was incorrect. Take care.

Never been quite clear on how Tow/Haul works on my 2013 Expedition (same chassis as an F150), with 5.4L V8 and 6-spd tranny. I think (but don't really know) I can achieve the same effect by switching into range 2 or 3 on the gearshift for engine braking on steep downhill grades. Really should experiment more, but usually too busy just negotiating curves and wishing I were already down.

[CharlesinGA]

Originally Posted by John in Santa Cruz

diesels don't have a throttle body so they don't actually have that much engine braking, unless they have a 'jake brake'... diesels control the engine acceleration by how much fuel they inject.

Indeed, diesels do not have throttle bodies, however RAM/Cummins since 2007, Ford since 2012, and GM also from about 2012, incorporate very effective exhaust brakes. New Diesel trucks from the big three incorporate the gearing down and exhaust brake together to maintain a downhill speed.

Jake Brakes mentioned are generally only found on Class 8 trucks and not on light or medium duty diesel powered trucks (250/2500 up to 650/6500 models) which will have the exhaust brakes. Older diesels can easily have an exhaust brake added to them, either a physical unit installed in the exhaust pipe near the engine, or simply electronics in some GM models to utilize the turbo's exhaust brake capability that sits unused because GM failed to incorporate such software from about 2005 up to 2011.

Diesel exhaust brakes are much more effective than the engine braking from a gasoline engine (which is nothing to sneeze at).

It didn't take me long to figure out I needed an exhaust brake for my 2003 Cummins and I spent $1500 and several days working on it (slowly) to add a PacBrake system to my RAM2500. (grin!) very effective, totally manual control for mine, toggle switch and select the proper gear on the six speed manual. I flip the switch to tell the Cummins computer that I want the exhaust brake to operate, and the computer operates the brake based on throttle position, and engine temperature.

Charles

[John in Santa Cruz]

Originally Posted by MrLynn

Never been quite clear on how Tow/Haul works on my 2013 Expedition (same chassis as an F150), with 5.4L V8 and 6-spd tranny. I think (but don't really know) I can achieve the same effect by switching into range 2 or 3 on the gearshift for engine braking on steep downhill grades. Really should experiment more, but usually too busy just negotiating curves and wishing I were already down.

I just tested the tow/haul mode on the new-to-me 2019 Expedition Limited, which has the Ecoboost 3.5L engine, with the 10L80 10 speed transmission... It definitely runs in lower gears, and it downshifts sooner when you're braking down a hill. I found it in 2nd going up a 35 mph 5% grade, when I drive the same truck without a trailer, it might be in 5th or 6th on that same hill at that speed.

[Bea]

Originally Posted by John in Santa Cruz

I just tested the tow/haul mode on the new-to-me 2019 Expedition Limited, which has the Ecoboost 3.5L engine, with the 10L80 10 speed transmission... It definitely runs in lower gears, and it downshifts sooner when you're braking down a hill. I found it in 2nd going up a 35 mph 5% grade, when I drive the same truck without a trailer, it might be in 5th or 6th on that same hill at that speed.

Congrats on your new Expy John!!! A mighty fine looking tow vehicle! Our 2017 Expy has the 3.5 EB with heavy duty tow package and even with our 6 speed transmission it tows our Escape like a charm.

However, the one thing that was initially confusing to me was learning how to tow with the tow/haul mode on. Like you mention, in the tow/haul mode it shifts down rather quickly when going downhill (which is fine, doesn't bother me) but then it has a tendency to stay in a lower gear (usually 2nd or 3rd gear) a little too long - even when you give it more gas, towards the bottom of the hill.

So after spending some quality time on the Expedition Forum, I learned that I can turn the tow/haul mode button off when I want it to release from the low gears, so I can pick up speed more comfortably (in higher gears) at the bottom of the hill. Then at the bottom, when the road is fairly level again, I turn the tow/haul mode back on again.

I don't have a Hill Decent mode (made me look...rats!) but I do have the Hill Start assist mode, which I use when I am backing the trailer up on our driveway with an incline - a very helpful feature that really does help keep it from rolling when I take the foot off the brake. Was not aware of the new Hill Decent mode before this - so will be fun to hear how folks like it...

[JohnK]

Small turbo charged engines have seemed to be getting good "towing" reviews since they were introduced. We tow with a 5.3 V8 which has great downhill holding capacity. I'm curious how the smaller displacement engines achieve holding power without coming close to their max RPM limits. Maybe holding the load on long steep grades with these small displacement engines is actually achieved by automatic wheel braking rather than engine braking?

[John in Santa Cruz]

On my expedition, near as I can tell the 'hill descent mode' is mostly intended for offroad use, at low speeds.

btw, anyone with the Ecoboost 3.5, and probably most any other direct injection engine, especially turbocharged ones, should change the oil every 5000 miles no matter what the factory recommends, and only use high quality full synthetic oils of the recommended viscosities. For example:

https://www.youtube.com/watch?v=eHPSgqipk-E

[Dave Miller]

I like tow/haul mode rather than hill decent on my 23 Expedition. Tow haul will hold to a very low gear and you rarely use the brakes. I used hill decent towing my 19 down an extremely steep switch back road into the snake river canyon. It held the speed at 5mph but was in 3rd gear and I could smell brakes at the bottom.

My complaint is that you have to remember to set tow haul each time you start, even though it knows you have a trailer connected.

I took my expedition in for service at 7000 miles when I got back home with my new 19. The dealer wondered why a came in early!

[MrLynn]

Off-topic, but as long as we've got some Expy owners here. . .

My General Grabber HTS 60 tires are six years old; only 37K on them, but tread is getting low, and with winter coming, I'm thinking of replacing them. The Generals seem OK; Tire Rack also suggests Continental Terrain/Contact H/T, Cooper Discoverer HT3, and Michelin Defender LTX M/52. Local mechanic can get whatever I want (there was a rebate on the Generals when I got them). Any thoughts/experience/recommendations/warnings?