What do you guys think of the Tow/Haul DFM hack?

[Ponyboy]

I gotta admit, when my truck broke 10K it seemed like the DFM got more aggressive, like.....a lot more aggressive. Constantly coming on at the slightest release of the accelerator.

Then I saw a post on FB about pushing the tow/haul button while driving in normal mode and it shuts off both the auto-stop and DFM. Sure enough, that actually works but then I got to wondering if the truck does anything special while driving in that mode. Does the transmission have different shift points, Is it bad for the truck to drive around all the time in this mode?

I didn't want to ask on FB because that place is a cesspool of asshats and Trailboss versus ZR2 dorks and there are actual GM folks in this forum.

 

[Matt Trakker]

What about L9? Does that do the same thing?

 

[CanZr2]

I gotta admit, when my truck broke 10K it seemed like the DFM got more aggressive, like.....a lot more aggressive. Constantly coming on at the slightest release of the accelerator.

Then I saw a post on FB about pushing the tow/haul button while driving in normal mode and it shuts off both the auto-stop and DFM. Sure enough, that actually works but then I got to wondering if the truck does anything special while driving in that mode. Does the transmission have different shift points, Is it bad for the truck to drive around all the time in this mode?

I didn't want to ask on FB because that place is a cesspool of asshats and Trailboss versus ZR2 dorks and there are actual GM folks in this forum.

Higher line pressure, better engine braking and higher shift points. Dont think it will hurt anything, just not drive as nice... Buy a Range module to disable the DFM.

 

[securityguy]

What about L9? Does that do the same thing?

It does.

 

[securityguy]

Higher line pressure, better engine braking and higher shift points. Dont think it will hurt anything, just not drive as nice... Buy a Range module to disable the DFM.

Range will tell you NOT to install this on a 2022-2023 refresh truck...the ECM's are different and it may create adverse effects. They do NOT recommend this at all. I spoke to their engineer for about 20 minutes on this topic.

 

[CanZr2]

Range will tell you NOT to install this on a 2022-2023 refresh truck...the ECM's are different and it may create adverse effects. They do NOT recommend this at all. I spoke to their engineer for about 20 minutes on this topic.

When they come out with one. They said they were working on in it.

 

[securityguy]

When they come out with one. They said they were working on in it.

Your post made it sound like buy one now...and you can't.

 

[ZR2NYC]

What about L9? Does that do the same thing?

i do the L9..

 

[securityguy]

i do the L9..

I stopped doing the L9 since there were several posts it won't matter if DFM kicks in or not. The tow haul mode won't matter either.

 

[Matt Trakker]

I stopped doing the L9 since there were several posts it won't matter if DFM kicks in or not. The tow haul mode won't matter either.

so there is no way to disable DFM?

 

[securityguy]

so there is no way to disable DFM?

Sure there is. L9 and Tow Haul. They just won’t prevent the dreaded lifter failure from happening.

 

[Matt Trakker]

Sure there is. L9 and Tow Haul. They just won’t prevent the dreaded lifter failure from happening.

Thanks for the clarification.

 

[Jasnak]

It does.

I use this method. Get better fuel economy too I leave it in L9

 

[Stevebag383]

Sure there is. L9 and Tow Haul. They just won’t prevent the dreaded lifter failure from happening.

Was there someone out there that never allowed there engine to enter DFM that had a lifter failure? Just wondering!

 

[Ereed45]

so there is no way to disable DFM?

L9 will disable but you still have the garbage lifters that will eventually fail. The only real fix is to have those bad lifters replaced with good ones, but it is very expensive (if you can even get the parts).

 

[scubatech]

Check out Scoggins Dickey Chevrolet. They have a video on this problem and how to get rid of it. You have to replace the cam, lifters and valley cover. Also the lifter solenoids that activate the lifters during DFM. I would imagine the ECU would need to be flashed to show the missing solenoid. They are a high performance Chevy dealer, I think they are in Florida.

 

[securityguy]

Check out Scoggins Dickey Chevrolet. They have a video on this problem and how to get rid of it. You have to replace the cam, lifters and valley cover. Also the lifter solenoids that activate the lifters during DFM. I would imagine the ECU would need to be flashed to show the missing solenoid. They are a high performance Chevy dealer, I think they are in Florida.

Yep...but, have you looked at the cost? If you know how to do it yourself, maybe viable. Otherwise, I would just take my chances while I am under warranty.

 

[scubatech]

Yep...but, have you looked at the cost? If you know how to do it yourself, maybe viable. Otherwise, I would just take my chances while I am under warranty.

I agree SG. I was just trying to point out what's really needed to eliminate the issue altogether. If I worked at a Chevy dealer I would see about installing a 6.6 liter LT8, without all that crap. The engines look the same overall. I would imagine you may need to flash or change the ECU. But maybe you could fudge on the warranty a bit and pull it off! You never had any issues with this on your GMC's I'm assuming?

 

[securityguy]

I agree SG. I was just trying to point out what's really needed to eliminate the issue altogether. If I worked at a Chevy dealer I would see about installing a 6.6 liter LT8, without all that crap. The engines look the same overall. I would imagine you may need to flash or change the ECU. But maybe you could fudge on the warranty a bit and pull it off! You never had any issues with this on your GMC's I'm assuming?

Nothing yet and hoping it remains that way. I am now getting the message that my truck cannot update eventhough it is in PARK. Says to take it to the dealer. I think I read others were experiencing this too. Not sure of the solution, but the truck is operating just like it always has...AWESOME!