Towing RPM's

[toddrswenson]

I've towed a lot over the years, but I want to get everyone's opinion here. Is it better to tow at a higher RPM and avoid downshifting when going up hills. I drive a 2009 Suburban, 6 speed transmission. If I don't let the transmission go past 4th gear I can run 65 MPH @ 2500 RPM. If I let it go into 5th gear I am running about 2100 RPM but any incline in the road causes it to downshift into 4th gear.

[Zach@n3]

Does it have a transmission temp gauge? Wondering gears with a load behind it makes the temp go up. If you like to tow at 65 mph you wont be hurting that engine at all running 2500 rpm all day long. Probably easier on the engine and transmission if it's going to shift all the time. I tend to tow in OD but I live in Indiana so it's all flat. 5.3L I assume?

[OKWAKEBDR]

Constant shifts is much harder on your transmission than 2500 rpm is on your engine. 2500 rpm is nothing. If it was 4k plus, that'd be a different story.

Heat is the killer.

Like Zach said - watch your temp guage (hopefully you have a transmission temp guage along with the engine temp).

[toddrswenson]

It's the 5.3 and I believe it has a transmission temp read out. I would prefer to tow at 75. I'm leaving on a 7 hour trip tomorrow. I've done it before but it was with my 97 Ski. A little lighter but not much.

[DanielC]

In the bad old days, before you had engine computer controlling everything, this was easier to answer. If you held the same throttle position with your foot, and downshifted, and vehicle speed went up, you are probably better in the lower gear. A higher engine RPM loads the engine less, allows more cooling fan speed, and can result in the engine running cooler.

I would also suggest the gear in the transmission that is 1 to 1 is more efficient, or has the least power loss.

Another issue is the torque converter locked up, or not. If the torque converter is unlocked, then it is generating more heat, and that heat represents a power loss, that could be going to the rear wheels.

There is probably a lot of useful information in your vehicles owners manual.

[Zach@n3]

The 5.3 is a little down on torque. What does it do when you run 75? I trick I used to use when towing with my 5.9 R/T was to anticipate the truck going up hill. There was a hard spot in the gas pedal that was the point at which the TQ would unlock and it would shift out of overdrive. I would go ahead and mash it down to just before that point and pulling hills it would stay locked up and not downshift unless it was an extreme grade. When towing slightly under powered there are little tricks that take a bit more driver input.

The 5.9 wasn't down on torque at all but the Cruise Control would take it to that downshift point a little too fast and kick it out of OD. I hate wondering gears.

[ers906]

I know it wont help during your trip scheduled for tomorrow, but consider getting a monitor which plugs into the diagnostic port in your vehicle. It makes towing much less stressful on long trips, with the ability to monitor your transmission fluid temp, engine temp, exhaust gas temps, mileage/gallon, etc. Had one installed in my excursion before towing 1400 miles round trip, and took much of the stress out of the drive (although the GF needing bathroom breaks hourly almost caused me a nervous breakdown). I had the EDGE evolution on my f150, and now have the EDGE CTS in the excursion. Big recommendation