How do y’all feel about towing 3500lbs in Drive?

[Cut Wagon]

I own a Lawn Care company and I tow a lot. However, it’s relatively light duty overall. Trailer is about 3500lbs and on weekends I tow a boat that weighs the same. I just bought this 2019 Suburban Z71 5.3. I don’t like the way it shifts in Tow Haul mode. Last few days I just put it Drive on L5 for around town. 55mph max. Tows better that way when driven properly. I’m pretty easy on it when towing. Pretty much speed limit all the time. Wondering if 3500lbs is too much for regular Drive on the tranny? Any opinions?

I hope to do a Blackbear style engine/trans tune in the near future.

 

[Joseph Garcia]

I would think that your truck would easily handle that weight around town in regular drive mode. I rarely tow, so I'll rely on my fellow Forum members who do tow, to give you a much more complete answer.

 

[Cut Wagon]

I posted this in wrong forum. Meant to be 2015-2020 Engine and Drivetrain.

 

[Joseph Garcia]

@Fless will make the thread relocation for you.

 

[Marky Dissod]

I own a Lawn Care company and I tow a lot. However, it’s relatively light duty overall. Trailer is about 3500lbs and on weekends I tow a boat that weighs the same.
I just bought this 2019 Suburban Z71 5.3L. I don’t like the way it shifts in Tow Haul mode. Last few days I just put it Drive on L5 for around town. 55mph max.
Tows better that way when driven properly. I’m pretty easy on it when towing. Pretty much speed limit all the time.

Wondering if 3500lbs is too much for regular Drive on the tranny? Any opinions?

I hope to do a Blackbear style engine/trans tune in the near future.

What, specifically, don't you 'like' about 'the way it shifts in Tow/Haul mode'?
Better you describe your complaint(s), closer BlackBear will satisfy you, possibly the 1st time around.
Whole purpose of Tow / Haul mode is to 'possibly' sacrifice 2 or 3MpG to protect the engine from lugging,
and protect the transmission from upshifting too soon / failing to downshift soon enough.
The less (unnecessary) shifts, the longer the transmission will last; this depends on the load on the powertrain.
At least you put it in L5; don't forget to tell BlackBear about that, so you won't have to once it gets tuned.

Why do I have this inkling that you don't tow up steep hills much?
I will say that towing a 3500lb boat may be 'easier' than towing 3500lb of aerodynamically jagged stuff;
don't know if you'd want to do anything about that though.

 

[Cut Wagon]

You are right, no hills down here except for bridges, overpasses, and levees.

What I don’t like is that in Tow mode it’s goes way past what it should be. It’s acting like I’m trying to merge into traffic from a dead stop pulling 8k lbs. Revs way too high and long. I’ve had a lot of trucks and pulled lots of stuff. Never had one this. It’s usually the opposite where I’m wanting to carry the gear further, this Burb is the other way.

 

[Marky Dissod]

You are right, no hills down here except for bridges, overpasses, and levees.

What I don’t like is that in Tow mode it’s goes way past what it should be. It’s acting like I’m trying to merge into traffic from a dead stop pulling 8k lbs. Revs way too high and long. I’ve had a lot of trucks and pulled lots of stuff. Never had one this. It’s usually the opposite where I’m wanting to carry the gear further, this Burb is the other way.

No, it just goes past what you PREFER, because it's erring on the side of caution, for once.
You said it yself "It’s acting like I’m trying to merge into traffic from a dead stop pulling 8k lbs.
Revs way too high and long. I’ve had a lot of trucks and pulled lots of stuff. Never had one this.
It’s usually the opposite where I’m wanting to carry the gear further, this Burb is the other way."

So you ask BlackBear to split the difference - just mind that if you WERE towing 8000lb,
it was already programmed pretty well, for once, especially if you had hills to deal with.

You want Goldilocks? Get tuned, and ask for what you want as accurately as you can -
and don't forget that you have TWO shift tables available.

You REALLY don't need to fear RpMs with these engines;
they're spec'd & built to handle 4500RpM all day long.

 

[Cut Wagon]

I’m also not very used to this Burb. Never had anything higher than 3.73. Coming from gasser 3/4 ton. I’m going to drive it all day tomorrow in Tow mode and see how it goes.

 

[Marky Dissod]

I’m also not very used to this Burb. Never had anything higher than 3.73. Coming from gasser 3/4 ton.
I’m going to drive it all day tomorrow in Tow mode and see how it goes.

Well, I checked your VIN, you've a 6L80E with 3.42.

If I’m going through the expense and trouble to swap gears, it’s 4.10 all day everyday.

I'll begrudgingly admit that, unless you Tow/Haul HEAVY, 3.42 will do fine, as it's already rated to tow 7500lb.
A;ready mentioned that 4.10's benefits likely outweigh its very minuscule drawbacks.

 

[Cut Wagon]

This is the first vehicle I’ve ever had that is below 3.73. This 19 Burb. I mistakenly posted my 4.10 comment to the wrong thread. Still applies, but I screwed up the comment.

 

[swathdiver]

This is the first vehicle I’ve ever had that is below 3.73. This 19 Burb. I mistakenly posted my 4.10 comment to the wrong thread. Still applies, but I screwed up the comment.

The gearing in your truck with 3.42s is better than any 4-speed truck you've ever had with anything numerically lower than 4.30 gears.

You're not really towing enough weight to use Tow/Haul mode. It only provides a benefit when you are at 75% or more of your GCWR. So your rig's GCWR is 14,000 pounds and if the truck and trailer weigh more than 10,500 pounds, then Tow/Haul ought to be used.

The transmission cooling system on those K2s needs work. If you have the 6L80, she needs the lower temp thermostat or "flip the pill" to keep it alive. Run the severe service schedule for normal use and if you are towing all the time, change the fluid every 20K miles or so.

 

[Cut Wagon]

I’m aware I have a 3.42. My PPE themostat by pass came in today.

I drove in tow haul all day pulling trailer. It’s 1st and 2nd gear that is my issue. It just holds those two gears way too long for my use. Once it’s in 3rd and 4th it’s fine, but until then it’s screaming for no reason. I’m doing 25mph and it’s at 2500-3500 and won’t up shift without me completely taking my foot off the throttle and even then it will stay up there. I mean I’m being very easy on it bc I’m in residential areas and lots of stop lights etc. I prefer it in Drive for my needs.

 

[swathdiver]

I drove in tow haul all day pulling trailer. It’s 1st and 2nd gear that is my issue. It just hold those two gears way too long for my use. Once it’s in 3rd and 4th it’s fine, but until then it’s screaming for no reason. I’m doing 25mph and it’s at 2500-3500 and won’t down shit without me completely taking my foot off the throttle and even then it will stay up there. I mean I’m being very easy on it bc I’m in residential areas and lots of stop lights etc. I prefer it in Drive for my needs.

That's because it's not meant to be used with that little weight. When you are pulling enough weight, the shifts feel normal.

Run it in drive and think about it no more.

 

[Cut Wagon]

Yeah makes sense. So 1st and 2nd gear can be tuned? Never messed with tuning before, I guess it’s just lowering the shift point RPM right?

Is the Silverado/Sierra truck like that too?

What’s funny is that on my 2016 Ram 2500 5.7 Hemi 3.73 I just git rid of, I actually drove it Tow/Haul full time. Even when not towing. It was so poorly geared. It was perfect in Tow Haul. Same thing with my C6 Corvette. Drive was terrible, Sport mode was perfect. I would say Sport Mode on the Vette is the same thing as Tow/Haul on truck/SUV.

 

[Marky Dissod]

So 1st and 2nd gear can be tuned? Never messed with tuning before, I guess it’s just lowering the shift point RpM right?

Is the Silverado/Sierra truck like that too?

What’s funny is that on my 2016 Ram 2500 5.7 Hemi 3.73 I just git rid of, I actually drove it Tow/Haul full time. Even when not towing. It was so poorly geared. It was perfect in Tow Haul. Same thing with my C6 Corvette. Drive was terrible, Sport mode was perfect. I would say Sport Mode on the Vette is the same thing as Tow/Haul on truck/SUV.

When tuning the tcm, part-throttle shifts are adjusted by road speed, not RpM.
Once WOT is in effect, shift commands initiate by RpM to protect the engine & transmission from over-reving, but that's over 4875RpM.
Under that, shift commands initiate by MpH. This is why tire size and gearing are important too.

Every gear, every shift can be tuned and improved, ESPECIALLY the ones you THINK you're ok with now -
GM OE 'programming' can always be improved upon to suit the tastes of any individual.
To the ecm & tcm, the Sielvierrado are mildly different versions of sufficiently similar hardware,
although they are differentiated by calibration part numbers to make tuners' lives a pain in the arse.
(Once I got good at tuning an IronBlock LT1-Caprice wagon, I could tune any F- or Y-car with an IronBlock LT1 as well.)
If you know how to tune a 5.3L in one vehicle, you pretty much know how to tune any 5.3L, and can extrapolate the other related engines/vehicles with some study.
If you know how to tune a 6L80 in one vehicle, you pretty much know how to tune any 6L80E, and so on, etc.

 

[Cut Wagon]

After a little over a week of towing my light duty load in Drive, it works pretty good. If it was hilly down here, probably different story, but it’s as flat land as you can get. MPG is 11 while towing. About the same as my Ram 2500 5.7 Hemi. I was hoping for 13. I’m going to install my PPE by pass today on the tranny. Still looking at getting a tune etc.

 

[buckwild27]

Just some informational tidbits in terms of rear-end gear ratios the higher the numbers the lower the gears are. And in terms of shifting the transmission when the rpms too high you want it to upshift not down shift. As for the tow/haul being the same as sport mode no disagreements there in terms of tuning, but be aware unless I got the one village idiot that works there they told me they can't change anything with the tow/haul tables even though I know it can be basically turned into a sport mode button for the trucks and suvs. Which is why I won't use Black bear.

 

[Cut Wagon]

I’m fully up on gear ratios and shifting

 

[Marky Dissod]

... be aware, unless I got the one village idiot that works there, they told me they can't change anything with the tow/haul tables,
even though I know it can be basically turned into a sport mode button for the trucks and suvs. Which is why I won't use Black bear.

this is actually pretty unsettling; guess they want to avoid making changes to the Tow / Haul table.

 

[buckwild27]

this is actually pretty unsettling; guess they want to avoid making changes to the Tow / Haul table.

That was my take on it. I'm not dropping that much cash if you can't make changes I want to tables that can be changed.