Towing ?

[Rivernut]

Towing my rig for the first time today w/new truck. I know you are supposed to tow out of O.D. 60mph/3000rpm's. What would be a safe rpm to tow at w/o being too hard on engine or tranny? Towing cap. is 4850 lbs. trailer is 1100/1200.

[upnorth]

I had to have a tranny rebuilt and the mechanic who rebuilt it said to never tow anything in OD, that is unless I wanted see him again.

[Rivernut]

That's what I have heard before.

[Valv]

I just towed a 21ft Starcraft Islander from Seattle, WA to MN at 70mph on highway in OD. That's 1,750 miles, my truck has 253,000 miles, I only toke it out OD when climbing mountains.

If you drive on interstate OD would be ok, if you start feeling transmission is shifting continuously in and out of OD , then take it out, your fuel mileage will decrease to a point.

[Rivernut]

Thanks Valv. I took it out for a stretch and it never came out of OD. I guess I"ll experiment a little and go from there. It has a tranny cooler and the person that bought it new ordered 410's in the rear. I think it should be fine.Thanks again.

[Kyle Sandberg]

Ok, please someone clarify this for me please. I have a 17' starcraft. If I'm going to drive it up north on 169, do I need to have OD on or off? Is the excessive RPMs hard on the engine/tranny?

[Powerstroke]

Excessive RPMS are not terribly hard on your engine. Towing in OD or out of OD is more about the tranny than your engine. The engine will survive as long as your oil is in good shape and the cooling system is up to it.

If you feel that your tranny keeps shifting because it can't hold a speed in OD then you should take OD off and drive the rest of the way out of OD. Having all the shifting is allowing extra slipping on the torque converter. This builds up excess heat and heat is what kills trannys. Wear will not ruin your tranny as fast as heat.

[cold one sd]

At 65 mph my truck runs about 1,900 rpms in OD and about 2,500 out of overdrive. My previous truck didn't have overdrive and ran about 2,500 rpms in third gear. Both trucks have 373 gears. Running with your tow vehicle out of overdrive is no harder on your engine than towing with an older truck without overdrive. I don't know what would be considered excessive rpms.

[Jeremy airjer W]

I see older GM trucks/suvs with baked trannies do to the overdrive being used for towing. I also see a lot of front wheel drives do the same thing. I just had a lumina that we replaced the trans in a little over a year and a half ago. The trany was baked with less than 25k miles. Turns out they towed a small trailer in overdrive all the time!

When in doubt take it out, slow down a bit, and enjoy the ride!

[BobT]

I usually try to pay attention to what the transmission is doing. If it seems to be shifting quite often I'll take it out. Otherwise, I leave it in.

Bob

[Surface Tension]

A lot of this depends on your tow vehicle. A 1 ton truck might no need to come out of overdrive to tow. A mini Van in most cases will need to be out of overdrive.

Look at how a tranny responds(without towing). Kick the throttle down to pass and it'll downsift right away, thats fine and won't hurt the tranny.

Example: When towing in overdrive with cruise on you come up to a small incline. The load starts to increase the on the engine, the cruise slowing asks for more fuel. This goes on and eventually the accelerator is depressed so far that the tranny down sifts. Thats terrible on the tranny, not so much the down shift but the prolonged point with increased load up to the point of shifting is bad news. What can be worse is driving in OD but be at a load not quite to the point where your tranny sifts out of OD.

So its hard to say when and when not to tow in OD other then to say it depends on the vehicle. If your coming out of OD on the smallest of inclines then you shouldn't be in OD on the flats.

[BobT]

Agreed. You don't want to be riding on that edge too much because the transmission will run too hot and perhaps under too much constant hydraulic pressure (I think?).

Bob

[Bassboy1645]

Hmm this clears up alot of my questions....Ive heard soo many things but the tranny in my 91 f150 pulling my rig about 1200-1400 pounds shifts way more out of overdrive than in overdrive. I leave OD on and I havent had a problem. I think it deals with the weight and the size vechile/load ur pulling.

[Pat K]

The higher RPMs won't hurt the engine and will help cool the tranny. Like most have responded if the tranny is costantly shifting, run it out of OD, if the tranny doesn't shift between 3rd and OD constanly you should be ok running in OD.