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Towing RVs

Is there a problem leaving the overdrive on while towing an RV on a highway or interstate?

Most vehicles recommend not using overdrive when towing. In your case you’ve got a 2500 series which is heavy duty. You didn’t mention the size of your trailer, so the answer could depend on how much of a load you are pulling.

I pull a 2 horse trailer with a Toyota Sequoia and I have a button for OD off. I push the button and tow with the OD off. Sometimes on a long gradual downhill I’ll drop the transmission into overdrive for the downhill run then push OD off again as soon as it flattens out. On a steep hill I don’t do this so I get some engine braking. Under any circumstances you don’t want to ride your brakes when pulling a trailer.

The possible harm is that you might shift it to death.

This is for you to assess.
Factors like weight, speed, and terrain play into the transmission’s need do downshift. Too much of that and you’ll want to turn off overdrive.

You decide , one circumstance at a time and switch on/off as needed.

Don’t know about your Dodge, but my Suburban’s manual said absolutely to shift out of overdrive.

Could be, read the manual, mine says if frequent upshifting and downshifting occurs put it in d3, and do not use cruise control.

On flat roads with a small light weight RV, it is up to you. Through hills or mountains with a larger trailer, you will risk hurting the transmission because of excessive downshifting.

What does your owner’s manual say on the subject? What is the trailer’s gross vehicle weight rating?

I agree…it’s not a yes or no question. So much depends upon the tow vehicle capabilities and the weight (drag) of the trailer being towed. Generally, working anywhere near tow limits of vehicles, err on the side of caution as owner’s manual recommends.

Small one ton GMC dump body that I drive for deliveries has excellent auto that is computer controlled…you tow or have heavy loads and computer changes shift points and gear selection automatically, even providing engine braking when accelerator is let off on grades and feature is activated.

With my motor home pulling my small trailer and motorcycle, I can barely feel the weight of the trailer and motorcycle. However, I choose to err on the side of caution, even if it means using more fuel.

Your vehicle will tell you in short order if it will tolerate the overdrive or not…If you notice it constantly shifting in and out of OD and having trouble maintaining highway speed without downshifting, then, for sure, lock out the OD…But if it will cruise along comfortably in OD without downshifting except on noticeable grades, you can use it…

This sounds most reasonable to me. The lighter loads I often tow don’t seem to affect shift points, I keep in OD. But, speed is as big a consideration as drag of tow increases exponentially. I would be as aware of upper speed limit as well even if transmission maintains OD. I believe drive train can be overstressed, even if OD is maintained at higher speeds.