Just need to make sure....

When pulling my boat, when I get up to cruising speed and the road is flat I will drive with overdrive on. Is this bad or should I run with overdrive off?

When pulling my boat on a road that has hills (not big, but big enough to drop a gear when in overdrive) is it ok to drive with overdrive off for long distances? I believe around 65-70 mph I would be running 3000+ rpm.

Just want to make sure I am not killing the truck.

 

Your overdrive module will likely overheat even on flat ground while towing (at least with my experience).

 

So it's better to run 3200+rpms? I can't imagine taking a long road trip with the truck screaming like that. It seems like it would be hard on the engine, not to mention all the gas you'd waste. Please explain

 

back in the day 3200+rpms would be hard on the motor but todays engines are made for that. I understand you don't want to waste gas but think of it this way would you rather spend a little extra in gas or replace your tranny? Overdrive is made for unloaded vehicles on the highway using it while loaded can tear trannys up.

 

3200 rpms?? Mine runs at 2500 when towing my camper.

 

i disagree. if you are on flat highway at a steady speed there is no problem turning the O/D back on.

The O/D off button is there to keep the trans from hunting for gears. because of the transmissions nature, it will try to find the highest possible gear based on the load that is put on it. if you are cruising and take your foot off the throttle, the trans will go to O/D, but as soon as you even touch the throttle, the load gets too much and the trans kicks down to a more suitable gear. When towing, the extra weight only exacerbates the situation. all this in and out action creates slippage and heat, and those are Automatic transmission killers.

As long as the transmission wont be constantly kicking in and out of O/D, its ok to turn it back on, i just suggest to flip it off again BEFORE it does it on its own under load, ie. climbing hills, passing, etc.

 

My old 1970 Suburu 360 sedan cruises around 5800rpm on the highway (and yes it still runs fine)

Another thing I have found is that on my 318 dodge I many times get BETTER mileage in 3rd gear than in 4th, even when in heavy wind on the highway not just when pulling, I think the engine lugs too much in 4th and must slip making 4th a waste if your trying to tow anything.

Cheers
Ryan

 

I tow alot with all my trucks, mostly motorcycle/ATV trailers. I always leave the OD on when the truck isn't straining or kicking down, i.e. flat roads. As soon as I hit the hills I turn it off. Yet to replace a tranny on any truck I've owned in the past 20 years.

 

i would like to get MonteC's opinion, he knows more about this.

 

I would disagree with your disagreement. I was towing on what were essentially flat surfaces (North Dakota) while towing a UHaul last summer and just about fried my OD module because I had overdrive on. And while I will admit that my driving is "spirited" this occurred even with my dad driving.