Any harm in using tow/haul mode during normal driving?

glendon66 · July 8, 2019

I recently had some exhaust installed and I've noticed that turning on haul/tow mode really makes the sound even more enjoyable. Loud growling downshifts, higher shift points and it almost sounds like I'm driving a manual transmission. Anyone else driving their truck like this and other than lower gas mileage does anyone have any downsides to driving this way?

RACERX7775 · July 8, 2019

I dont think it will allow it to hurt itself. But it does make for some high rpm downshifts. I have the Borla ATAK on my truck so I understand wanting to hear the exhaust. But sometimes it'll downshift and hit upwards of the 5k rpm range.

SkiDooNick700 · July 8, 2019

13 minutes ago, RACERX7775 said:

I dont think it will allow it to hurt itself. But it does make for some high rpm downshifts. I have the Borla ATAK on my truck so I understand wanting to hear the exhaust. But sometimes it'll downshift and hit upwards of the 5k rpm range.

daaaang your tow haul mode will downshift to that high of an rpm with no load?? I don't recall mine ever doing that lol although I haven't used it a ton!

newdude · July 8, 2019

No harm other than fuel mileage really. Manual mode with tow/haul off would accomplish the ear candy just as well IMO. If you still have AFM enabled, I have noticed that tow/haul will let it stay in 4cyl longer than with it off at times.

Quote

Tow/haul mode is a function within the vehicle's software/calibration that optimizes transmission gear selection for operation during towing or with heavy loads. This optimization includes improving acceleration performance during launches, reducing shift busyness, assisting brake performance and speed control during engine braking situations, and improving vehicle speed control while requiring less throttle pedal activity.

In general, tow/haul mode maintains lower gears longer and increases shift pressures. It is designed to be most effective when the vehicle and trailer combined weight is at least 75% of the vehicle's Gross Combined Weight Rating (GCWR). Operation of tow/haul in a lightly loaded or non-loaded vehicle will not cause damage. However, there is no benefit to the selection of tow/haul when the vehicle is unloaded, and use of tow/haul mode during unloaded driving conditions will decrease fuel economy and may generate shift feel concerns.

Edited July 8, 2019 by newdude

ammoaddict · July 8, 2019

No harm other than fuel mileage really. Manual mode with tow/haul off would accomplish the ear candy just as well IMO. If you still have AFM enabled, I have noticed that tow/haul will let it stay in 4cyl longer than with it off at times.

Tow/haul mode is a function within the vehicle's software/calibration that optimizes transmission gear selection for operation during towing or with heavy loads. This optimization includes improving acceleration performance during launches, reducing shift busyness, assisting brake performance and speed control during engine braking situations, and improving vehicle speed control while requiring less throttle pedal activity.

In general, tow/haul mode maintains lower gears longer and increases shift pressures. It is designed to be most effective when the vehicle and trailer combined weight is at least 75% of the vehicle's Gross Combined Weight Rating (GCWR). Operation of tow/haul in a lightly loaded or non-loaded vehicle will not cause damage. However, there is no benefit to the selection of tow/haul when the vehicle is unloaded, and use of tow/haul mode during unloaded driving conditions will decrease fuel economy and may generate shift feel concerns.

Good info

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1SLOW1500 · July 8, 2019

The right answer is technically yes more damage. It will hold shifts and stay in gear longer. This equals more trans wear and your tcc (converter). The amount is small but much greater then the normal(pattern x). Also trans temp will increase as well and as we know the warmer the temp the quicker it breaks down.
One would also assume when you are in this mod and enjoying the noise you are also a little more agressive with the throttle.
I would highly recommend a electric cutout. They have really dropped in price any exhaust shop can handle it. Or but the bolt in one. Cut out a small section of pipe and the pre fab piece bolts in with stainless band clamps. Run cable in truck mount switch and you have it all. Any gear and mode and more noise.

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slide187 · July 8, 2019

I do it at a light when I know I need to be in front of the slow poke next to me. Then I shut it off once I get going. [emoji48]

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bg1988 · July 9, 2019

9 hours ago, glendon66 said:

I recently had some exhaust installed and I've noticed that turning on haul/tow mode really makes the sound even more enjoyable. Loud growling downshifts, higher shift points and it almost sounds like I'm driving a manual transmission. Anyone else driving their truck like this and other than lower gas mileage does anyone have any downsides to driving this way?

less MPG and engine braking.. it's fine I use it sometimes my self (only to disable Auto stop) on CA-110 (Stop sign entrance ) other wise i don't use it

That is the only way i can get to 0 to 40-45 in a few seconds... since i will have the power of the ICE and electric motors

Edited July 9, 2019 by bg1988

Jacoby · July 9, 2019

It won’t cause any issues at all other than annoying the other people around you.

m3n00b · July 9, 2019

13 hours ago, 1SLOW1500 said:

The right answer is technically yes more damage. It will hold shifts and stay in gear longer. This equals more trans wear and your tcc (converter). The amount is small but much greater then the normal(pattern x). Also trans temp will increase as well and as we know the warmer the temp the quicker it breaks down.
One would also assume when you are in this mod and enjoying the noise you are also a little more agressive with the throttle.
I would highly recommend a electric cutout. They have really dropped in price any exhaust shop can handle it. Or but the bolt in one. Cut out a small section of pipe and the pre fab piece bolts in with stainless band clamps. Run cable in truck mount switch and you have it all. Any gear and mode and more noise.

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I've been looking at cutouts. Which is recommended and where should it be placed? Was thinking pre-third cat.

1SLOW1500 · July 9, 2019

Understand that it will.be even louder then the exhaust. But in the straight section of the cat back. Right where the exhaust system bolted on. So it opens right at the cab and bed split. Aim it at the side of the truck just so fumes get out.
Note it will be super loud. But if that is your thing.

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L86 All Terrain · July 9, 2019

These transmissions fall apart under normal and AFM conditions, specifically the torque converter. My 6.2L got a new converter, then burnt up a stator shaft and I ended up getting a reman 8L90e. I do drive aggressive in that truck, but that isn't what caused my tranny issues. Just bad parts. Anything you can do to not beat on them will increase life. It will also grade brake for you in tow haul, so it will downshift sometimes when you are coasting down a hill when you are not expecting it to. Kind of like when cruise control wants to drop 3 gears and rev to 4500rpm to keep you at 60mph up that hill instead of relaxing a bit and losing 5mph at the top.

1SLOW1500 · July 9, 2019

These transmissions fall apart under normal and AFM conditions, specifically the torque converter. My 6.2L got a new converter, then burnt up a stator shaft and I ended up getting a reman 8L90e. I do drive aggressive in that truck, but that isn't what caused my tranny issues. Just bad parts. Anything you can do to not beat on them will increase life. It will also grade brake for you in tow haul, so it will downshift sometimes when you are coasting down a hill when you are not expecting it to. Kind of like when cruise control wants to drop 3 gears and rev to 4500rpm to keep you at 60mph up that hill instead of relaxing a bit and losing 5mph at the top.

You are right the bad part is the converter in many cases but also the tune gm uses is set to slip the clutch all the time. Makes for a smoother ride but the equals wear. The trans will hold 600rwhp but once debris go thought the trans and the fluid breaks down you are fighting a losing battle.
The 90 has bigger output shaft and housing other then that no advantage. And the 8 speed just has 2 overdrive gear sets.
Some people upgrade the trans clutch packs and even mill down the carrier and ad more clutches but that just allows it to hold more power the computer still tells the clutch in the stall to slip. And that is where a performance or multi disc convert is key to life.

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Mileguru · July 9, 2019

12 hours ago, bg1988 said:

CA-110 (Stop sign entrance )

Yeah, those Highland Park freeway entrances suck!

bmartinez2086 · July 9, 2019

Honestly I dont think it will hurt it in fact it might do it a favor. I've seen I'm my truck the shift up or down are much smoother and accurate when I tow haul mode. The downshift without it on can be harsh at times but with it on its butter smooth.