Safely long-haul towing with a 2006 Z71 Tahoe

[Stev1e]

Hello all,

Did some searching and didn't find anything that seemed germane to my question in the last couple of years, so here's my situation:
I have a 2006 Tahoe Z71 2WD with 230k miles that I intend to tow a 20-foot-long heavy trailer with. When I say heavy, assume near, at, or slightly over vehicle tow capacity.
I have a weight-distributing hitch, and successfully towed my heavy trailer from outside Columbia, SC to the Big Bend area in FL using back highways. The trip went well, albeit slow, and was primarily flat with some gently rolling hills. I was anxious for most of the drive and didn't want to try pushing past about 57 MPH for fear of wearing out the engine or transmission. The move was made in July or August, and I had no temperature issues (sadly, I cannot say whether I have a transmission cooler installed; I just don't know right now).
It's nearly time to take my heavy trailer from Florida to Maine. I have a flattish route picked out, and intend to be rolling in the 50-60 MPH max range again, placing the trip at just over 3 10-12 hour days of driving. As a holiday gift, I was given a OBDII scanner, with the intention that I use my phone as a transmission temperature gauge to help ease my mind as I pull my heavy trailer to Maine.

The question is this: Is there a safe RPM range I can sustain over that distance? Are RPMs irrelevant and I should pay more attention to the temp gauges? What temp ranges should I be looking for for sustainable operation here? The intention is to take this trip in either August 2023 or May 2024, depending on weather and variables beyond my control.

As far as I'm concerned, if I pull up to my new home with my trailer and my Tahoe shakes apart into small pieces, I'll still be satisfied with the job well done. What I'm really trying to avoid is an on-the-road breakdown where I'm forced to do some absurd gymnastics to get the heavy trailer up to Maine.
I do have fairly extensive towing experience by distance, though it's traditionally been in this same Tahoe pulling a U-Haul car trailer with a 1965 Mercury Comet perched on it, so far from the slowest or most technical drive you can do.

 

[B-train]

Keep her in 3rd gear and don't be overly aggressive with the throttle. LS motors are rpm Champs and don't care running for extended hours like that. Fresh oil change and Trans service beforehand. Maybe even a diff service too if it's been awhile.

You'll have good airflow at 55-60 so temps won't be a problem. If you start creeping towards the 230 mark, you might want to slow down or give it a rest stop. Leave the truck running all the time for quick rest stops or fuel upside. Shutting off just heat soaks and cooks stuff.

 

[Scottydoggs]

i see or hear the word germane and this is all i can think of lol

 

[rockola1971]

LS based engines are built for high RPM longevity straight from the factory. Cruising 1800-2500 RPM...the engine wont care as long as its got enough oil and cooling system is working fine. Transmission.....dont even consider running in 4th with that kinda weight behind the tahoe. You'll burn the 2-4 band up in short order then you are screwed and will only have 1st and 3rd gear. Tranny fluid and filter service if it hasnt been done since last time you went on your long towing expedition. Grease your front end, ujoints if they arent sealed type and check coolant hoses for loose clamps and hose deterioration.

How much does the trailer and load weigh?

 

[Marky Dissod]

I have a 2006 Tahoe Z71 2WD with 230k miles that I intend to tow a 20-foot-long heavy trailer with.
When I say heavy, assume near, at, or slightly over vehicle tow capacity.

Since you did not say that your Z71 has 4.10 or 4.30,

Keep her in 3rd ...

... don't even consider running in 4th with that kinda weight ...

Stay out of 4th, AND stay in Tow / Haul mode.
Even if Dexron 6 can handle 239°F, I'd still be concerned if ATF temp got up that high.

A supplemental ATF cooler fan never hurts.
If you can have your pcm reprogrammed to improve towing durability, that can't hurt either.

As for engine RpM, above 2000RpM, which should not be too hard in Tow / Haul mode while avoiding 4th.

 

[Fless]

Look through your grill and if you have one it'll be between the grill and the A/C condenser:

 

[nonickatall]

From my humble view, It is not the towing, that is the problem, for the automatic teansmission, but the shifting. Each time when there is a shift, greater forces act on the clutches than usual. Therefore, drive as evenly as possible on the highway, and prevent strong acceleration, then the automatic does not care.

 

[Mudsport96]

As all have said, keep it in third gear and let 'er sing. My 06 Z71 has 3.42 gears in it. So ASSUMING yours has them too.

55 in 3rd is 2060ish rpms
75 in OD is 1966ish rpms.

So if you ever have done Interstate driving at 75 you have already driven your rig at RPMS you will be doing towing. You will just be moving slower.

1. Fresh oil change
2. CHECK ALL fluids
3. If the atf is anything but pretty red, i would probably flush it.
4. Book on tape ( Jurassic Park is about 13 hours lol) as it will be a long drive, 26ish hours at 55 from big bend to Biddeford maine( dont know where you are going, but i picked Biddeford as i know where that is lol. )

 

[Stev1e]

...Fresh oil change and Trans service beforehand. Maybe even a diff service too if it's been awhile...

Good point on the differential. I'm sure it's been a time and a half, so I'll make sure that's taken care of. Had planned on the oil change and the transmission service, particularly since "the truck" (growing up, my folks had a '99 Tahoe and a series of sportier cars. Ergo, "the car," and "the truck." The '06 replaced the '99, but the '99 is still in the family, ticking away after 330k.) does a lot of sitting lately.

i see or hear the word germane and this is all i can think of lol...

Thank you.

...dont even consider running in 4th with that kinda weight behind the tahoe. You'll burn the 2-4 band up in short order then you are screwed and will only have 1st and 3rd gear...
...Grease your front end, ujoints if they arent sealed type and check coolant hoses for loose clamps and hose deterioration...

Well noted on the 2/4 band. I'm a glutton for good fuel economy, but I'll grit my teeth and keep it to 3rd rather than burning up a transmission for no point.
Will add those items to my list of services prior to heading out. May not end up passing the coolant inspection, but we'll find out in a few months, I suppose.

...Even if Dexron 6 can handle 239°F, I'd still be concerned if ATF temp got up that high...
...If you can have your pcm reprogrammed to improve towing durability, that can't hurt either...

Nice to have a number to 100% avoid, thank you.
In this case, I think "can" and "understands who to ask to do that" are different factors. Any recommendations where to start on that?

Look through your grill...

An excellent single-sentence tutorial; I do have a transmission cooler!

From my humble view, It is not the towing, that is the problem, for the automatic teansmission, but the shifting. Each time when there is a shift, greater forces act on the clutches than usual. Therefore, drive as evenly as possible on the highway, and prevent strong acceleration, then the automatic does not care.

Sometimes the most obvious information is the hardest to come up with on your own. 1. duh. 2. of course. 3. DUH. 4. Thank you, I honestly hadn't considered that. Than again, I've driven a lot of C4 transmissions (65 Ford 3-speed automatic), so I'm used to breathing wrong and the thing blowing up.

As all have said, keep it in third gear and let 'er sing. My 06 Z71 has 3.42 gears in it. So ASSUMING yours has them too...
...So if you ever have done Interstate driving at 75 you have already driven your rig at RPMS you will be doing towing. You will just be moving slower....
...4. Book on tape ( Jurassic Park is about 13 hours lol) as it will be a long drive, 26ish hours at 55 from big bend to Biddeford maine( dont know where you are going, but i picked Biddeford as i know where that is lol. )

I just did a 30-minute scramble trying to figure out what my gearing is, but unfortunately, with the glovebox having been replaced and today not being the day I'm going to jack my rear end up and watch the driveshaft rotate to calculate it, I can't advise what the gearing is... for now.
Another duh moment that is incredibly helpful to have said out loud by somebody else. Thank you.
I laughed a lot at #4. (Oakfield, which is 20 miles shy of Houlton. Basically I-95 from Portland to Canada lol)

 

[Marky Dissod]

Nice to have a number to 100% avoid, thank you.

Welcome.

In this case, I think "can" and "understands who to ask to do that" are different factors.
Any recommendations where to start on that?

My personal recommendation, from personal experience, is
pcmperformance.com
As mail order tuners go, he's among the best.
That said, fairly sure there are other talented pcm / ecm / tcm tuners to whom you can physically bring your vehicle so it can be more personally tuned.
I'm sure this or other forums will give you a few local suggestions.
You let your tuner know that you're towing a wee bit more than GM's suggested limit, and that you want Tow / Haul mode to be programmed to avoid 4th under, at least, 74MpH - a road speed you must never achieve while towing - and you're golden.

If you have electrical fans, the tuner will program them with heavy towing in mind.