Engine brake use

[jkxtreme]

We are on a one year tour of the western states of the USA, and for the past few weeks we've been in Idaho, Montana, and Colorado. The mountains out here are pretty impressive but do pose a challenge as we go down those mountains. We've been as high as 11,000 feet with some of the down hills as long as seven miles. Our tow vehicle is a 2023 Ford F350 dually with the high output 500 hp diesel engine. The truck has worked really well, especially the engine brake function. When using the cruise control, the computer applies both the truck / trailer brakes and the engine brake to control vehicle speed. However, on one of the really long, steep down hill stretches, my truck brakes over heated and the computer shut off the cruise control. Thankfully, the engine brake has two modes that can be used when not using cruise control. 'On' mode and 'Auto' mode. When 'On' is selected the engine brake is activated as soon as I let off the gas pedal. When 'Auto' is selected, the engine brake isn't activated until I tap the brake pedal. We've discovered turning off the cruise control and just using the engine brake in 'On' or 'Auto', controls the truck speed on those long down hill stretches, without activating the truck and trailer brakes. No more overheated brakes. However, on two of the long straight down hill stretches we had to briefly apply the brake pedal to keep the speed down to where we were comfortable... only a few seconds each time. Most of the time, on those down hill stretches, we do not use the cruise control, and select the 'On' function for the engine brake. Thoughts or comments?

 

[jsb5717]

We've traveled those mountains a few times...yes, they are beautiful and impressive and will put your truck to the test.

I might suggest that if your truck brakes are overheating then perhaps your trailer brakes aren't properly adjusted. They should be doing more of the work to minimize the impact on your truck's brakes.

Our truck is a 2015 so we don't have all of the latest tech. I do know that between the exhaust brake, trailer brakes, and truck brakes that managing long, steep downhill runs is fairly painless and stress free. We haven't had any of those systems fail...yet. We also haven't had truck brakes overheat...even when cruise control is engaged. Of course, once you tap the brakes it's no longer engaged. My experience is that with the exhaust brake engaged on Auto that an occasional tap on the brake pedal maintains a safe downhill speed.

 

[Carl n Susan]

I don't use cruise control on my 2015 Ford. We drive steep mountains frequently. We are returning from a trip to the Western Region Rally that took us through CA, ID. MT SD, WY, UT, and NV. I use the exhaust brake and truck gears to control the downhill speed of the truck and RV. I rarely apply the brakes except to slow to the appropriate speed for the next lower gear. I save the truck and trailer brakes for emergency stops.

 

[Lee-C]

Two train of thoughts from someone who drove semi's for many years in a prior lifetime. Thought one is that I implore you to never use cruise control through mountainous areas. Today's modern pickups have way more than enough power to weight ratio to get one into serious trouble before they even realizes the seriousness of their situation

Thought two is that if you have indeed overheated your truck brakes, then an ounce of prevention is worth way more than a pound of cure. Have your brakes thoroughly inspected by a fully capable and reputable service center.

 

[VagabondLove]

I too have the recent Ford with the HO engine, and use the automatic (vs ON) engine break all of the time. I never know when the autopilot is engaging the truck and trailer brakes as well as using the engine to perform the braking solo. If I keep the full autopilot on, I suspect I am authorizing the autopilot to use whatever it needs (including the supplemental regular braking) to control speed, and it likely does not have any inputs re brake temperatures to help optimize/balance out the various braking options.

When we travel in the mountains, what we tend to do is NOT be on full autopilot when performing extended descents, but to just disengage the autopilot speed control and only activate the automatic engine break. If I really need to slow, I do a hard pump on the foot pedal brakes until the engine downshifts, then we operate in the new speed range, without anything but the engine brakes.

One thing I have really been thinking about is adding an internal LED or light tied to the center brake light to let me know in the cockpit when the physical brakes are actually being applied (which will trigger the third tail light). I agree, not knowing what the autopilot is doing is not ideal and does not give us a chance to properly manage our tow vehicle. I just never thought that it would end the way yours did.

Of course, a laser temperature meter is always used at all stops to make sure all four trailer wheels and tires are operating consistently, and to validate that the autopilot doesn't mess things up!

 

[Majorpolk]

We have a 2011 Duramax Deleted Dually and are currently in Colorado. Been over almost every high pass here. I set the Exhaust brake to on down shift to low or second gear, and drive about 23 mph. I seldom touch the brakes. Makes the passes simple. Key is drive your truck don’t let the other vehicles influence how you drive. Sure, pullover when there is room or another lane, but do it when it is best for you. Those other people will get to their destination just fine just maybe a few minutes later.

 

[PSFORD99]

Well , this surprises me ,some of the replies . My truck is a 2014 Ram 3500 . I can set my cruise for 5 mph lower then the speed I want to go down any mountain grade I’ve been on here in Utah , Idaho , Montana, and Wyoming towing my fifth wheel. It holds that speed . If it’s 50 I’m comfortable with , then the cruise is set to 45 , it gains that 5 mph , and holds there .

As far as I know the electronics in my truck do not activate the brakes on the fifth wheel when in cruise , and I’ve got EB on , on a descent . Of course that’s with no brake input . I do have disc brakes on the fifth wheel , which I wouldn’t have anything else after having fifth wheels with , and without disc brakes.

 

[ImagineCamping]

No cruise on the big hills, right pedal go, left pedal tap to activate exhaust brake, shift to low and use manual shift up and down to hold a gear on steep descents. This is on a 2025 duramax 3500 Dually, no ford experience but would imagine you have similar capability.

 

[PSFORD99]

No cruise on the big hills, right pedal go, left pedal tap to activate exhaust brake, shift to low and use manual shift up and down to hold a gear on steep descents. This is on a 2025 duramax 3500 Dually, no ford experience but would imagine you have similar capability.

It’s apparent Ford nor Chev have caught up to capabilities of the Ram Cummins , especially the exhaust brake . I do none of that to hold descending , set cruise as said before 5 under what I want to run , and it does its thing . No
tapping brakes or anything, absolutely no manual shifting.

 

[RMcNeal]

I don't know about the Chevy or RAM, but my Ford power stroke will hold speed downhill with the engine brake. I don't use cruise control, up hill or down, but I do use the Tow/Haul mode which enables the engine brake. Even on 7-9% downhill grade it will hold back the truck and trailer no problem. Start off the mountain slowly, tap brakes to engage the engine brake and the truck does the rest.

 

[PSFORD99]

I don't know about the Chevy or RAM, but my Ford power stroke will hold speed downhill with the engine brake. I don't use cruise control, up hill or down, but I do use the Tow/Haul mode which enables the engine brake. Even on 7-9% downhill grade it will hold back the truck and trailer no problem. Start off the mountain slowly, tap brakes to engage the engine brake and the truck does the rest.

So you are saying , your ford power stroke will hold speed downhill . what does that mean . If you are going 50, it stays at 50 ??? What I found out doing what you do , sure it holds , but then depending on the grade , you are back on the throttle . The exhaust brake will slow me down to the point I need to get back on the throttle , only to repeat this multiple times . So then you get back to speed ,only to let off to starting slowing down again ,and back on the throttle .

I have yet to come of a grade with my fifth wheel doing what I do now ,and never getting on the brake ,no tapping the brakes anymore like you describe ,to me it was an annoying process . As I have said If it's 50 I want to run , I set the cruise for 45 , it will gain that 5 mph ,and never over ,the exhaust holds me at 50 the entire grade . I have been on some long grades , cruise set ,and only if there are some curves that require slower speed is the only time I need to get on the brakes , and then it's back to that getting slowed down to the point of needing to accelerate again ,but instead I just hit resume . Easy process , done this for years now with my Ram Cummins 6.7

Yes there have some winding roads where I can't do that , but I deal with the same exhaust brake slowing to the point I am back on the throttle to repeat over ,and over until out of that situation . My point is although it's apparent some do it differently dealing with long mountains , the modern diesel's do a good job with their exhaust brake . I do know the old Powerstrokes were non existent in that department , having owned one , the 7.3 . White knuckle driving coming off long mountain grade with the fifth wheel in tow .

 

[RMcNeal]

That's not my experience with my truck, however my truck has been modified with a special towing tune and other emissions modifications. I guess that could make a significant difference.
When starting down a steep grade, I get to the speed I want and tap my brakes. The truck will downshift or do whatever is needed to maintain that speed without increasing. Once I reach level ground I can push the accelerator to disengage the exhaust brake and continue driving normally.
Honestly I had my truck modified prior to getting the current rig and my prior rig was half the weight, so it may very well be the tune and mods. It's not stock, so ymmv.

 

[flyingjack]

PSFORD: exactly same with my 2023 Silverado Duramax

 

[PSFORD99]

That's not my experience with my truck, however my truck has been modified with a special towing tune and other emissions modifications. I guess that could make a significant difference.
When starting down a steep grade, I get to the speed I want and tap my brakes. The truck will downshift or do whatever is needed to maintain that speed without increasing. Once I reach level ground I can push the accelerator to disengage the exhaust brake and continue driving normally.
Honestly I had my truck modified prior to getting the current rig and my prior rig was half the weight, so it may very well be the tune and mods. It's not stock, so ymmv.

Sorry if I sound skeptical ,but I see no way any EB will hold a constant speed when you have let off the throttle , and applied the EB , the whole purpose is to slow the truck on a descent . Unless I am misunderstanding what you are saying . I see no way it can hold a constant speed , either it can't handle the weight ,and descent , and gain speed or like mine it slows to the point where I need to get back on the throttle . The reason why I say I use the cruise , and then whatever it is set at ,it holds within 5 mph.

I do know my truck has two EB settings , one is auto ,which I don't use , and possibly it does what you are describing . I may try that ,but I can't see where a towing tune ,and emissions modifications would do anything for the EB . What a towing tune ,and emission modification means to me , is the truck has been deleted , and has the tuner ,which is needed to allow the truck to run correctly with the deleted emissions .

 

[PSFORD99]

PSFORD: exactly same with my 2023 Silverado Duramax

Same as what I do with the cruise on a descent when towing a fifth wheel ???

 

[RMcNeal]

I see what you're saying. While going downhill the EB will hold my speed but once I level out it will slow down. I just use the EB to control speed on the downhill.

 

[twindman]

EB when using cruise control will pretty much handle things unless on a really steep grade. I went from Montana on I15 (I think) to AZ and had to brake once and get on the gas once. And only have a 6 speed. These newer ones have 10 speed and should handle it even better.
Of course this won't work on a 9 or 10 per cent grade! LOL

 

[PSFORD99]

EB when using cruise control will pretty much handle things unless on a really steep grade. I went from Montana on I15 (I think) to AZ and had to brake once and get on the gas once. And only have a 6 speed. These newer ones have 10 speed and should handle it even better.
Of course this won't work on a 9 or 10 per cent grade! LOL

Same here 6 speed Cummins 6.7 . Have yet to meet a hill here in Utah , Idaho , Wyoming , and Montana that EB on cruise won’t handle , of course when having to slow to handle a curve .

 

[flyingjack]

PSFORD, same states and no problem as well. I70 thru CO; cruise and EB up and down at 5-10 below the speed limit so as not to impact the speeders. But, I did travel an 8% downhill grade in southern CO that EB wouldn't handle and I had to massage the brakes a little before getting back to business as usual.

 

[WhatExit?]

We are on a one year tour of the western states of the USA, and for the past few weeks we've been in Idaho, Montana, and Colorado. The mountains out here are pretty impressive but do pose a challenge as we go down those mountains. We've been as high as 11,000 feet with some of the down hills as long as seven miles. Our tow vehicle is a 2023 Ford F350 dually with the high output 500 hp diesel engine. The truck has worked really well, especially the engine brake function. When using the cruise control, the computer applies both the truck / trailer brakes and the engine brake to control vehicle speed. However, on one of the really long, steep down hill stretches, my truck brakes over heated and the computer shut off the cruise control. Thankfully, the engine brake has two modes that can be used when not using cruise control. 'On' mode and 'Auto' mode. When 'On' is selected the engine brake is activated as soon as I let off the gas pedal. When 'Auto' is selected, the engine brake isn't activated until I tap the brake pedal. We've discovered turning off the cruise control and just using the engine brake in 'On' or 'Auto', controls the truck speed on those long down hill stretches, without activating the truck and trailer brakes. No more overheated brakes. However, on two of the long straight down hill stretches we had to briefly apply the brake pedal to keep the speed down to where we were comfortable... only a few seconds each time. Most of the time, on those down hill stretches, we do not use the cruise control, and select the 'On' function for the engine brake. Thoughts or comments?

I have a 2021 F350 Super Duty 6.7L diesel SRW SB and it’s powerful enough to accelerate uphill towing my 3120RL 5er.

I only use cruise control on normal freeways/highways, nothing with major elevation change. The engine brake, both modes, is an awesome tool and a must-use.

One thing I didn’t see you mention was manual downshifting which is another crucial tool to use.