Using the cruise control

[CAG]

Originally Posted by Camper_bob

The problem is that the cruise control can't see a grade coming. So it will allow the rig to drop as much as 5 mph without downshifting. Then it will downshift to 3rd gear at WOT trying to gain back that 5 mph (which it won't be able to do).

Instead, it's better, smarter, and easier on the equipment if you give it a little throttle AHEAD of the grade, get one gear downshift, and maintain speed as you go up the grade. Then the rig is already in the appropriate gear at the appropriate RPM to maintain speed up the grade instead of trying to make up lost speed and momentum.

That tactic tends to work better in hilly terrain or in an urban area where you're going up and down overpasses. If you're pulling a long, steep grade, you probably need a different tactic.

If you hit enough of a grade and bleed enough speed, the cruise control will cut off anyway. It's designed to maintain a set speed at whatever cost, not to drive for you.

That is what tow/haul is for. It changes shift points and the torque converter so that you are not caught on the bottom end of the current gear. It also does a great job of controlling downhill trips. The Allison is especially good at this, I found with two Duramax over the years and the few trips I have done so far with the Jayco I have found it to be as good at maintaining speeds.

[Camper_bob]

Originally Posted by AKRUEBBE

My transmission (Aisin) will downshift when my set speed drops 2 mph and can hold my speed on any grade I've yet to experience. I believe the 4.10 ratio attributes to that.

Diesel is a totally different ballgame. You have torque low in the RPM band, and overall more torque in general than a gas engine.

A gas engine generates it's maximum torque VERY high in the RPM band, so if it bleeds a little speed, it wants to go WAY up in RPM to pull max torque to make up that speed, but on anything more than a gentle grade, it can't do it. So what you end up with is your engine spinning 4500-5000 RPM trying to gain the speed you lost the whole way up the grade. When if you just manage it a little, you can get it in the right place to pull the grade nice and easy.

Also, in T/H mode, the cruise will let more speed bleed off before it tries to do something about it. With T/H mode off, it will begin trying to make up speed at around 2 mph drop. But I never drive my rig (Class C MH) without T/H mode on.

FWIW, I managed the cruise the exact same way in my Ram 2500 gasser towing my 28BHBE heavy. Goose the throttle a little bit ahead of a grade, get the transmission to downshift one gear, pull the grade at your set speed nice and easy. In that truck I also had the ability to set a maximum gear. So if I was pulling really hilly terrain and the truck was shifting frequently, I would just manually set a lower gear, let the engine rev where it needed to and save the transmission from shifting too much. My MH on E-450 chassis does not have that ability (or at least it's not quite as advanced anyway).

All this is to say that the function of the cruise control is to maintain a set speed. It doesn't care what's happening on the road or under the hood or in the transmission. It's your job as the driver to monitor all of those other things and adjust accordingly.

[CAG]

Diesel is a totally different ballgame.

Perhaps you missed the part where I mentioned that I have found the Ford to do as well. I have been impressed with the transmission in tow/haul mode. I have not found it shifting too much at all. It seems to shift at the correct times and with the correct results. What I have found with most all transmissions on inclines, and we have some goodies here in Arizona, if you are trying to control shift points on your own, you are either jamming the throttle to the floor trying to get a shift, or just blocking traffic up Sunset Point climb because you waited too long and now can't get speed no matter what gear.

So far I have not found any difference between my previous diesels and this gasser in climbing mountain grades here. Cruise in tow/haul shifts where it should, maintains speed and I don't see the RPMs going to places they should not be. I have not seen a reason to take over from the computer.

I also might add, that considering our long, varying climbs here trying to find the right place, by ear, is going to be an effort in futility.

[Camper_bob]

Originally Posted by CAG

Perhaps you missed the part where I said that I have found the Ford to do as well. I have been impressed with the transmission in tow/haul mode. I have not found it shifting too much at all. It seems to shift at the correct times and with the correct results. What I have found with most all transmissions on inclines, and we have some goodies here in Arizona, if you are trying to control shift points on your own, you are either jamming the throttle to the floor trying to get a shift, or just blocking traffic up Sunset Point climb because you waited too long and now can't get speed no matter what gear.

So far I have not found any difference between my previous diesels and this gasser in climbing mountain grades here. Cruise in tow/haul shifts where it should, maintains speed and I don't the the RPMs going to places they should not be. I have not seen a reason to take over from the computer.

I also might add, that considering our long, varying climbs here trying to find the right place, by ear, is going to be an effort in futility.

Okay, then I think there's something wrong with my rig and cruise control then. Same with my truck. And the truck before that, my other truck, and my Jeep...

And FWIW, all of this is completely different if I'm not towing a TOAD. When I have just the rig, cruise works just fine on its own most of the time. But I almost always have the Grand Cherokee hooked up out back, so I have to manage the "computer".

In my experience, especially driving through urban areas or rolling hills, the transmission shifts constantly and does so across 2-3 gears. As I'm approaching a hill/overpass, the cruise in tow/haul will bleed off 5 mph. Then the transmission downshifts to 3rd and runs at WOT at that dropped speed. While climbing the grade (which the rig does just fine), but it cannot make up that speed. It will attain the desired set speed as it crests the grade, upshift, then roll down the other side nice and easy, using engine braking if necessary to control speed. Then as I approach the next grade, almost immediately after rolling off the last one, it does the same thing over again. Drops 5 mph, drops 2 gears, screams all the way to the top. It will do this over and over and over all day long if not managed, and it will cook the transmission. Because as I said, the cruise cares ONLY about speed; not about where the engine and transmission should be to properly and efficiently pull the grade.

Since apparently my cruise is broken or not working correctly, I choose instead to slightly goose the throttle at the bottom of the grade. NOT floor the pedal. If you just give it a little nudge BEFORE it starts to bleed speed, you can get it to downshift ONE gear. This puts the engine and transmission in the CORRECT place to pull the grade nice and smooth at my desired speed, WITHOUT dropping speed 5 mph, WITHOUT dropping 2 gears, and WITHOUT working its tail off at WOT to try to make up 5 mph or more of speed bled off at the bottom of the grade.

If the grade is longer or steeper, sure I will let the truck manage the transmission. And oftentimes that type of grade requires you to run at higher RPM to maintain speed. Fine, no problem. I will still goose the throttle to get one gear downshift at the outset to give the equipment a head start. Then let the truck do the rest.

But for variable and constantly rolling grades, the engine doesn't NEED to run at 5000 RPM with the trans in 3rd to pull the grades at 65 MPH; 3000 RPM in 5th is just fine, and in fact I can often GAIN speed there. But the cruise control NEEDS to run the motor and trans like that to try to make up lost speed.

But since the cruise control has been EXACTLY like this in everything I've ever driven, I don't think mine is broken...

[CAG]

Originally Posted by Camper_bob

Okay, then I think there's something wrong with my rig and cruise control then. Same with my truck. And the truck before that, my other truck, and my Jeep...

And FWIW, all of this is completely different if I'm not towing a TOAD. When I have just the rig, cruise works just fine on its own most of the time. But I almost always have the Grand Cherokee hooked up out back, so I have to manage the "computer".

In my experience, especially driving through urban areas or rolling hills, the transmission shifts constantly and does so across 2-3 gears. As I'm approaching a hill/overpass, the cruise in tow/haul will bleed off 5 mph. Then the transmission downshifts to 3rd and runs at WOT at that dropped speed. While climbing the grade (which the rig does just fine), but it cannot make up that speed. It will attain the desired set speed as it crests the grade, upshift, then roll down the other side nice and easy, using engine braking if necessary to control speed. Then as I approach the next grade, almost immediately after rolling off the last one, it does the same thing over again. Drops 5 mph, drops 2 gears, screams all the way to the top. It will do this over and over and over all day long if not managed, and it will cook the transmission. Because as I said, the cruise cares ONLY about speed; not about where the engine and transmission should be to properly and efficiently pull the grade.

Since apparently my cruise is broken or not working correctly, I choose instead to slightly goose the throttle at the bottom of the grade. NOT floor the pedal. If you just give it a little nudge BEFORE it starts to bleed speed, you can get it to downshift ONE gear. This puts the engine and transmission in the CORRECT place to pull the grade nice and smooth at my desired speed, WITHOUT dropping speed 5 mph, WITHOUT dropping 2 gears, and WITHOUT working its tail off at WOT to try to make up 5 mph or more of speed bled off at the bottom of the grade.

If the grade is longer or steeper, sure I will let the truck manage the transmission. And oftentimes that type of grade requires you to run at higher RPM to maintain speed. Fine, no problem. I will still goose the throttle to get one gear downshift at the outset to give the equipment a head start. Then let the truck do the rest.

But for variable and constantly rolling grades, the engine doesn't NEED to run at 5000 RPM with the trans in 3rd to pull the grades at 65 MPH; 3000 RPM in 5th is just fine, and in fact I can often GAIN speed there. But the cruise control NEEDS to run the motor and trans like that to try to make up lost speed.

But since the cruise control has been EXACTLY like this in everything I've ever driven, I don't think mine is broken...

That would leave only one element in this that could be the cause and that would be the operator

[TCNashville]

Originally Posted by Camper_bob

Okay, then I think there's something wrong with my rig and cruise control then. Same with my truck. And the truck before that, my other truck, and my Jeep...There's nothing wrong with your cruise, they all do that, lol.
In my experience, especially driving through urban areas or rolling hills, the transmission shifts constantly and does so across 2-3 gears. As I'm approaching a hill/overpass, the cruise in tow/haul will bleed off 5 mph. Then the transmission downshifts to 3rd and runs at WOT at that dropped speed. While climbing the grade (which the rig does just fine), but it cannot make up that speed. It will attain the desired set speed as it crests the grade, upshift, then roll down the other side nice and easy, using engine braking if necessary to control speed. Then as I approach the next grade, almost immediately after rolling off the last one, it does the same thing over again. Drops 5 mph, drops 2 gears, screams all the way to the top. It will do this over and over and over all day long if not managed, and it will cook the transmission. Because as I said, the cruise cares ONLY about speed; not about where the engine and transmission should be to properly and efficiently pull the grade. There's nothing wrong with trying to control the rig to prevent premature engine/transmission wear. This is why most modern transmissions have a manual feature.

Since apparently my cruise is broken or not working correctly, I choose instead to slightly goose the throttle at the bottom of the grade. NOT floor the pedal. If you just give it a little nudge BEFORE it starts to bleed speed, you can get it to downshift ONE gear. This puts the engine and transmission in the CORRECT place to pull the grade nice and smooth at my desired speed, WITHOUT dropping speed 5 mph, WITHOUT dropping 2 gears, and WITHOUT working its tail off at WOT to try to make up 5 mph or more of speed bled off at the bottom of the grade.This is what I do as well.

If the grade is longer or steeper, sure I will let the truck manage the transmission. And oftentimes that type of grade requires you to run at higher RPM to maintain speed. Fine, no problem. I will still goose the throttle to get one gear downshift at the outset to give the equipment a head start. Then let the truck do the rest. Agreed

But for variable and constantly rolling grades, the engine doesn't NEED to run at 5000 RPM with the trans in 3rd to pull the grades at 65 MPH; 3000 RPM in 5th is just fine, and in fact I can often GAIN speed there. But the cruise control NEEDS to run the motor and trans like that to try to make up lost speed.This is what I was saying in my earlier post.

But since the cruise control has been EXACTLY like this in everything I've ever driven, I don't think mine is broken...

It's not and trying to manage the rig in a way to prevent unnecessary wear due to unneeded RPM's is a good thing.

[Lake Huron]

Gas and diesels tow TOTALLY different. My 99 cummins is 215hp stock and my 01 yukon 5.3 is 285hp. My cummins will out pull my Yukon every day of the week. My cummins now has some " modifications" and will out tow my 15 duramax hands down. My cummins is 20 years old and I would say cruise on that was designed to care about speed because pretty much everything on it is mechanical. Today's vehicles dont have kick down cables attached to the trans from the throttle cable like the old ones did. My duramax tows differently than my "modified" cummins does. Newer trucks have computers that control everything, engine, trans, everything. The duramax senses load and torque to determine which gear to shift to and what rpm to keep speed. My cummins, it pretty much won't downshift because its s different animal in itself being "modified".

[Camper_bob]

Originally Posted by CAG

That would leave only one element in this that could be the cause and that would be the operator

Yes, the operator in this case is managing his equipment so that it works properly and efficiently instead of allowing a computer, that monitors a relatively small number of variables (which DO NOT include transmission temp, engine temp, driver comfort, etc), and has only one objective (to maintain set speed), to destroy said equipment.

If you start at one side of any major city (in Texas anyway), set your cruise to 65 (or any speed for that matter) and let the "computer" do its thing, you are causing unnecessary wear on your vehicle. The engine and transmission are perfectly capable of maintaining that 65 up and down the dozens of overpasses you'll drive over WITHOUT revving to 5000 RPM or shifting 6 or 8 times per overpass. But the cruise control will cause that exact situation (the excess shifting and revving) if left completely unmanaged.

Hauling across the flats without a grade in sight? No problem. Pulling long, relatively consistent grades? Piece of cake. Push the button, sit back and relax.

But constant rolling hills and overpasses? You shouldn't just push the button and go. The "computer" will literally let your transmission cook itself to death. And I don't know about the rest of you, but I don't like listening to my engine rev if it doesn't need to (driver comfort).

[Siamese]

Originally Posted by Camper_bob

Yes, the operator in this case is managing his equipment so that it works properly and efficiently instead of allowing a computer, that monitors a relatively small number of variables (which DO NOT include transmission temp, engine temp, driver comfort, etc), and has only one objective (to maintain set speed), to destroy said equipment.

If you start at one side of any major city (in Texas anyway), set your cruise to 65 (or any speed for that matter) and let the "computer" do its thing, you are causing unnecessary wear on your vehicle. The engine and transmission are perfectly capable of maintaining that 65 up and down the dozens of overpasses you'll drive over WITHOUT revving to 5000 RPM or shifting 6 or 8 times per overpass. But the cruise control will cause that exact situation (the excess shifting and revving) if left completely unmanaged.

Hauling across the flats without a grade in sight? No problem. Pulling long, relatively consistent grades? Piece of cake. Push the button, sit back and relax.

But constant rolling hills and overpasses? You shouldn't just push the button and go. The "computer" will literally let your transmission cook itself to death. And I don't know about the rest of you, but I don't like listening to my engine rev if it doesn't need to (driver comfort).

I think as long as you relate your experience with your equipment you'll be on solid ground. If you project that onto other equipment, your footing may get a little mushy.

The OP has a very similar rig to my own. An F-150 with tow mode, 3.5 eco boost, and a 10 speed transmission, pulling an appropriately sized trailer.

On flat to moderately hilly terrain, I can't out-shift the thing. Either going up hills, or coming down the other side. It doesn't hunt, and it doesn't over rev. It just picks the right gear, and my transmission temperature gauge has yet to disagree.

[TCNashville]

If I was towing a popup with my F-250 I'd use cruise all the time but I tow 9000lbs and I make the decision to limit the rpms going up a hill, not cruise control and still achieve the goal. Why let the engine rev to 5000 rpms when it doesn't have too. The 6R100 transmission in my truck thanks me every time. My next truck will have a 10 speed transmission which will be a completely different animal.

[billcf7]

Originally Posted by Camper_bob

The problem is that the cruise control can't see a grade coming. So it will allow the rig to drop as much as 5 mph without downshifting. Then it will downshift to 3rd gear at WOT trying to gain back that 5 mph (which it won't be able to do).

Instead, it's better, smarter, and easier on the equipment if you give it a little throttle AHEAD of the grade, get one gear downshift, and maintain speed as you go up the grade. Then the rig is already in the appropriate gear at the appropriate RPM to maintain speed up the grade instead of trying to make up lost speed and momentum.

That tactic tends to work better in hilly terrain or in an urban area where you're going up and down overpasses. If you're pulling a long, steep grade, you probably need a different tactic.

If you hit enough of a grade and bleed enough speed, the cruise control will cut off anyway. It's designed to maintain a set speed at whatever cost, not to drive for you.

This is not true for all vehicles. Some of the computers in vehicles now recognize roads previously traveled and will downshift automatically in cruise mode before they reach a grade whether it is up or down hill

[Big Steve]

Yeah I think I’ll try and get used to the truck n TT and avoid mountains or very hilly areas the first year . All though Iowa has those 3 sisters hills that are on I80 and can’t be avoided so I’ll cut my teeth on those long long hills up and down ! Keep going looks like a lot of great info and many things already I hadn’t even thought of !

[kblast523]

Originally Posted by Big Steve

So we’re planning too take 1 or 2 long trips this summer around 2000 miles round trip. I’ve pulled a TT all over Iowa but never really used my cruise I was younger and my knees weren’t wore out like now ... so I’d it a good idea to get too a long straight stretch up too speed and set the cruise?
Steve

You fail to mention what you tow with. Here's mu buck-two-fity...I do not use cruise with my Titan. I did with my 2015 F-150 2.7 EB and 2019 Ram 1500 HEMI.

Here is the reason: Left home two weeks ago headed west. Got to Canyon, disengaged the cruise until I got on US 60 headed toward Herford. It is slightly uphill ALL THE WAY to Portales (next state over) and I was a little concerned I was only getting 7.2 mpg into a 30 mph headwind, but not alarmed. Refueled in Herford, continued westward. Noticed my 5.6 32v V-8 turning between 3,000 and 4,000 mph, holding fourth occasionally going to third gear. At Portales, after going through town, forgot to re-engage cruise control, and suddenly the engine was turning 2,200 to 3,000 rpm, going to sixth FREQUENTLY. Since the engine wasn't 'revving' as much I left it alone for observation....Mileage according to the 'lie-o-meter' had fallen to 6.8 mpg. Still in a 20-30 mph headwind, but now ascending Sierra Blanca in order to get to Alamogordo...on the way up about a 6% grade I engaged the cruise...engine JUMPED to 4,800 rpm and dropped into 2nd gear...for no apparent reason. I had been pulling well at 3,200 rpm maintaining 63-64 mph. Disengaged cruise, it upshifted and again, 3,200 rpm. All this in Tow Mode. Trans temp stayed good, coolant temp stayed good, oil temp stayed good (all hidden in the confines of the Titan instrumentation). I continued on to Scottsdale over the next two days, no cruise. Lie-o-meter had registered as low as 6.9 but recovered after leaving Ft. Wilcox, Az to a more honest 8.7 mpg. Once underway moving to Phoenix Raceway around the NW side of town, again engaged cruise, same results...excess revs for what was needed to maintain speed. I had a 20-30 mph headwind 90% of the trip.

My F-150 2.7eb with a six speed would do a decent job of pulling and only occasionally would 'rev' while towing...it got about 10 mpg on premium. Transmission would run in 5th most of the time.
My Ram 1500 5.7 HEMI would rev like the Titan with or without the cruise. Coming back from Palo Duro Canyon over 4th of July, I saw sustained 4,800 rpm maintaining 60 mph into a 45 mph headwind. It had an eight speed and also ran in 6th while towing. The 3.21 rear end was poorly matched for the capacity of the truck. It made it make more 'noise' than it needed to. It's FCA's again, as it was re-acquired by the manufacturer in January, for other reasons.
My recent experience with these three vehicles and cruise control while towing is: Determine what the vehicle will do and do comfortably without blowing it's self up. If you are towing at close to max you will most likely experience a 'high rev' as the brains of the vehicle attempt to maintain speed. My return mileage without using cruise and over the same route, with 10-40 mph winds 'recovered' the lie-o-meter to 9.9 mpg trip average over 1,890 mile...all towing.

[RedHorse1]

I too use the cruise control. I like to cancel it on up/down grades tho. Uphill I let my speed drop and downhill I let it increase.

[Pickledill]

Level ground cruise, rolling hills,, foot!!! Cruise cannot see, I can. Better efficiency in rolling hills anticipating hills and increasing speed prior to ascending then controlling downshifts and roadspeed as it climbs.

[bykerhd]

I use cruise all the time towing or not.
Tow/Haul gets used on the Interstate highways but not on exits or other roads.
For some reason the Tow/Haul mode on both the Winnebago Class C V-10 and the new Jayco 31UL does NOT want to let the vehicles decelerate ?
Both vehicle's engines revved and the vehicles resisted slowing down.
Not a confidence inspiring scenario.

Something I am doing/not doing perhaps ?

[kblast523]

Originally Posted by bykerhd

I use cruise all the time towing or not.
Tow/Haul gets used on the Interstate highways but not on exits or other roads.
For some reason the Tow/Haul mode on both the Winnebago Class C V-10 and the new Jayco 31UL does NOT want to let the vehicles decelerate ?
Both vehicle's engines revved and the vehicles resisted slowing down.
Not a confidence inspiring scenario.

Something I am doing/not doing perhaps ?

Cruise control is by design, to maintain speed. If you are below the set speed it WON'T let the vehicle slow. It determines you need to SPEED UP. The revving engine is either trying to develop hp to speed up, or engine braking. If you are over the speed you set the cruise to, the transmission on my last three trucks downshifted to engage engine braking. Ford-Ram-Nissan, they all perform the same. I saw over 4,500 rpm in 3rd gear on the Ford descending one grade in NE Arizona. On the Ram and the Titan, it engages with or without the cruise engaged, to assist in braking when in tow/haul mode. I am not sure if the Ford did this or not.

[Camper_bob]

The engine braking on these E-450s in T/H mode is actually pretty decent for a naturally aspirated gas motor. In fact, in some cases, like while quickly slowing way down on a hairpin freeway exit, it gets a little too aggressive for my liking. But with cruise engaged, the engine braking does a really good job maintaining speed down a moderate grade IMO.

Forgot to mention the engine braking on my Ram 2500 6.4 gasser was pretty good too. Not quite as good as the E-450, but decent enough for sure. Nothing like a diesel, but still pretty decent.

[bykerhd]

Originally Posted by kblast523

Cruise control is by design, to maintain speed. If you are below the set speed it WON'T let the vehicle slow. It determines you need to SPEED UP. The revving engine is either trying to develop hp to speed up, or engine braking. If you are over the speed you set the cruise to, the transmission on my last three trucks downshifted to engage engine braking. Ford-Ram-Nissan, they all perform the same. I saw over 4,500 rpm in 3rd gear on the Ford descending one grade in NE Arizona. On the Ram and the Titan, it engages with or without the cruise engaged, to assist in braking when in tow/haul mode. I am not sure if the Ford did this or not.

What I have the issue with is when the cruise control is supposed ? to be disengaged when the vehicle brakes have been applied and the Tow/Haul mode is trying to keep the RPMs and vehicle speed up.

It doesn't seem to me that this should happen and yet it did with both vehicles on multiple occasions.
It is why I use Tow/Haul sparingly.

[kblast523]

Originally Posted by bykerhd

What I have the issue with is when the cruise control is supposed ? to be disengaged when the vehicle brakes have been applied and the Tow/Haul mode is trying to keep the RPMs and vehicle speed up.

It doesn't seem to me that this should happen and yet it did with both vehicles on multiple occasions.
It is why I use Tow/Haul sparingly.

Tow/Haul keeps you from: a) lugging the engine, absolutely DEVASTATING given todays oils, and b) over heating the transmission. After brake application, the system detects series of events the transmission reacts to by shifting to a lower gear, using engine braking. If you experienced engine revving AND increased speed it was most likely because of the 6+ degree descending grade you were on. The cruise control is to maintain a set speed. The t/h mode is to optimize transmission/engine operation and can sometimes be interfered with by the cruise control. Gravity and your right foot are all that is supposed to make your truck speed up.