Tow Mode & Gears

[George and Alora]

Hi,

I tow a 5000 pound camper long distances and often through hilly country. I do not have the big tow package but I ensure I always have tow mode switched on. I also have the 3.92 axle for optimal towing in certain gears.
So during these long trips one of the ways I amuse myself is by trying to keep the truck in the highest gear possible at cruising speeds. Up hills I try to keep it locked in 7th gear as long as long as possible. Or 6th gear as long as possible depending on the grade. I also think it saves gas.
The way I figure it is that this ain’t a manual transmission where you keep it in high gear and the engine lugs. The 2020 RAM computer wouldn’t let me do anything detrimental to the engine or transmission right?

 

[SD Rebel]

Actually, the manual states that you should be in the tow/haul mode even without a load in the mountains/hilly terrain, which will keep you in a higher rev range and extend the life of the transmission by reducing excessive shifting and heat buildup (pg. 287 of 2019 manual).

The computer will shift in a way that won't damage the truck. If you decide to lock the truck in 1st gear and drive at red line, that's a different thing.

 

[Richard320]

You won't hurt anything. You're keeping it from upshifting, not downshifting. If it's lugging, it'll kick down.

 

[SD Rebel]

Opps, I read it wrong at first, you are trying to keep it at the highest gear possible and lower your revs for fuel savings, either way, it won't hurt anything either way.

 

[silver billet]

Its up to you but I much rather prefer to keep the rpms up while towing, especially that kind of load. There are many times I force a downshift because it feels like the truck works more easily at higher rpms. Don't be afraid to keep it above 2000 rpms, the fuel savings (if any) isn't worth it to me. I'll even downshift before the hill begins to bite just because I know it will downshift anyway and this way the truck is making more power before it needs it, you're able to keep your speed up and prevent lugging.

So I don't have any proof or anything, but to me it seems better to let the engine rev while its working, lugging it builds up heat and probably kills your MPG anyway. Pretty sure these hemis like to rev.

 

[George and Alora]

Thanks for the input guys.

 

[IvoryHemi]

I love the downshift/ engine braking assist that Tow/Haul mode provides

 

[Ratchet]

I'm pulling about the same as OP. If I was worried about fuel mileage, I wouldn't have a truck nor a camper. Mine seems pretty comfy pulling 6K in tow mode. The engine braking is most welcomed.

 

[devildodge]

I am a bit confused. Trying to pull and stay in 7th gear?

Select 3rd and let that Hemi eat.

 

[KrustyKush]

We use our 2021 Ram 1500 to tow a 5000 lb Airstream. I love the tow/haul mode. Last month, we rode the coast highway from LA to where it ends in northern CA. This is hundreds of miles of twisty roads, up and down hills. That's where the tow/haul really shines. If you need some engine brake, just tap the brake pedal and the trans will shift down one notch, and stay there until you hit the gas again. Lovely.

 

[devildodge]

I am still confused by this thread.

You do realize peak horsepower is at 5600 RPM and peak torque at 3950 RPM.

Last night i had a load of logs in my truck and was fooling around with tow haul and gear selection.(doing a case study for another forum question) Now I know I only have the 6 spd but 2nd gear lockout and 45 Mph and barely near 3000 RPM...so in 7th gear...say 1500 RPM...why would you want to try to stay there climbing a hill.

I drove in 2nd for awhile enjoying the power right in tap. Even 3rd felt weak. 4th was annoying. 5th and 6th just stupid(although perfectly able to keep the load at speed).

Now...i much prefer my 8.0l V10 with manual 5 spds when moving loads...but I never, ever try to keep it in 5th.

What am I missing?

Very confused.

PFA

 

[SD Rebel]

I am still confused by this thread.

You do realize peak horsepower is at 5600 RPM and peak torque at 3950 RPM.

Last night i had a load of logs in my truck and was fooling around with tow haul and gear selection.(doing a case study for another forum question) Now I know I only have the 6 spd but 2nd gear lockout and 45 Mph and barely near 3000 RPM...so in 7th gear...say 1500 RPM...why would you want to try to stay there climbing a hill.

I drove in 2nd for awhile enjoying the power right in tap. Even 3rd felt weak. 4th was annoying. 5th and 6th just stupid(although perfectly able to keep the load at speed).

Now...i much prefer my 8.0l V10 with manual 5 spds when moving loads...but I never, ever try to keep it in 5th.

What am I missing?

Very confused.

PFAView attachment 101310

The OP is just trying to save fuel at the lowest rpm he can while highway cruising and was wondering if that will harm anything because he knows the higher rpm is what's needed for power.

His assumption is that he computer won't allow the engine to operate at an rpm that will harm it. We pretty much agree that is true, he is fine doing what he is doing to save fuel in those situations.

 

[devildodge]

The OP is just trying to save fuel at the lowest rpm he can while highway cruising and was wondering if that will harm anything because he knows the higher rpm is what's needed for power.

His assumption is that he computer won't allow the engine to operate at an rpm that will harm it. We pretty much agree that is true, he is fine doing what he is doing to save fuel in those situations.

He states towing a 5000lb camper.

I am interested to know how he gets it stay in 7th on hills.

I agree with what you are saying...which is exactly why I do not see him keeping it in 7th.

The gear selector lockout only locks out the upshift.

It will continue to downshift as it feels the need.

Just hoping he found a way to lock out the downshift.

Because if I could do that with my truck...select 3rd and stay in 3rd...i could finally convince my wife how stupid the Cummins is for our scenario.

Or...i just can not read and he is saying something totally different

 

[silver billet]

The OP is just trying to save fuel at the lowest rpm he can while highway cruising and was wondering if that will harm anything because he knows the higher rpm is what's needed for power.

His assumption is that he computer won't allow the engine to operate at an rpm that will harm it. We pretty much agree that is true, he is fine doing what he is doing to save fuel in those situations.

Agreed with most of that, but not necessarily that it "won't hurt anything". Lugging an engine while working it is not going to extend the life of the engine, it gets hotter than it needs to.

You're almost suggesting the TFL Truck approach; just put the hammer down and let the truck figure it out, but I find TH mode does not work properly in most situations. How can it? You have so many variations in terms of trailer load, hills vs straight, driving style, all while trying to minimize fuel and save engine life?

There are too many conflicting variables there, and I almost always override the gear on hills, the truck just does so much better when letting it rev more than the computer thinks it needs to. I have to think that overriding the gear most of the time can only help extend engine life, worrying about fuel consumption while towing is the completely wrong mindset if you plan to keep your truck around.

 

[KrustyKush]

Pulling our 5000 lb trailer, I find that often the trans will stay in 6th or 7th for long stretches, even running on fairly "level" surface, or what seems like level... it can be hard to tell that you're climbing. It will find 8th, but doesn't need to be in high gear. I am not concerned about higher engine speeds. I like the sound of the V8 in the upper realms of rpm. And sure not concerned about fuel economy. Pulling a trailer, gonna use more fuel, that's just the way it goes.

 

[SD Rebel]

Agreed with most of that, but not necessarily that it "won't hurt anything". Lugging an engine while working it is not going to extend the life of the engine, it gets hotter than it needs to.

You're almost suggesting the TFL Truck approach; just put the hammer down and let the truck figure it out, but I find TH mode does not work properly in most situations. How can it? You have so many variations in terms of trailer load, hills vs straight, driving style, all while trying to minimize fuel and save engine life?

There are too many conflicting variables there, and I almost always override the gear on hills, the truck just does so much better when letting it rev more than the computer thinks it needs to. I have to think that overriding the gear most of the time can only help extend engine life, worrying about fuel consumption while towing is the completely wrong mindset if you plan to keep your truck around.

But how are you going to lug an engine with a modern automatic. The engine can detect when it is being "lugged" and it should downshift as needed.

I agree with you on towing, I do it based on performance and longevity not mpg savings, but in the end, if he is in auto and in T/H mode (which he says he does), it shouldn't negatively effect anything, at least not in any measurably way.

If he wants to be light on the throttle to get it to go into a higher gear while on a straight highway, not sure how that hurts anything while in T/H mode.

 

[devildodge]

But how are you going to lug an engine with a modern automatic. The engine can detect when it is being "lugged" and it should downshift as needed.

I agree with you on towing, I do it based on performance and longevity not mpg savings, but in the end, if he is in auto without any gear limits, it shouldn't negatively effect anything, at least not in any measurably way.

Will his slightly higher heat in the tranny mean it will last a few thousand miles more in the scheme of a 200 - 300K lifespan? Not sure it can even have a tangible difference, too many other variables at play here.

Yes. It will not negatively affect anything because it will downshift.

So...he states he is holding 7th on hills...i want to know his magic.

5000lbs up a hill in 7th gear...maybe I need to tow on these hills.

 

[SD Rebel]

Yes. It will not negatively affect anything because it will downshift.

So...he states he is holding 7th on hills...i want to know his magic.

5000lbs up a hill in 7th gear...maybe I need to tow on these hills.

I can only guess he miswrote that, because there is no way to maintain speed on the hills without being on throttle. I'm only going off his main part of his post where he ask if the tranny would allow him to do something that would damage the truck.

 

[devildodge]

I can only guess he miswrote that, because there is no way to maintain speed on the hills without being on throttle.

Now you see where I am at. And as he states about a manual transmission...if he tried that he would definitely have issues.

 

[devildodge]

My 8.0l V10 has 450lb ft at 2400 RPM AND IS FLAT all the way to redline. With or without 5000lbs in tow in 5th gear on a hill...the engine is gonna let me know...hey dumb ***...how about a down shift or 2.

Not in reply to this thread...but to towers in general...lock that Hemi in 4th gear, go take a drive...better yet...do 3rd, stay in it, let up and get back on it...let me kno how much you smiled.

There is no way I would make it my goal to stay in 7th...which I believe is an overdrive gear.

Not sure which gear in the 8 spd is 1:1...but in mine it is 4th and 4th makes it feel like a truck. And allows you to modulate the throttle without downshifts.