overdrive or not

[hisey1]

i have a 2001 ford expedition that i've towed lots of boats with. i had a guy tell me NEVER tow with overdrive turned on. Always turn it off. I've never thought much about it but is it something i need to do every time or not? lost the owner's manual to my truck 2 days after i bought it so i cant refer to that.

 

[gstanton]

Re: overdrive or not

If the tranny is "hunting" back and forth, take it out (off). If it is staying in one gear most of the time, you're OK.<br /><br />I assume you DO have an aux transmission cooler?

 

[Terry Olson]

Re: overdrive or not

Gstanton is right - watch your tach while towing in overdrive. You'll see it drop a couple hundred RPM when the torque converter locks up - which means that it is no longer allowing slippage. This is the most fuel efficient but when the load is too great the torque converter will unlock as evidenced by an increase of a couple hundred RPM. If the need for additional power is significant it'll unlock, then downshift a gear. You don't want it locking and unlocking often or worse yet downshifting often. Every shift means transmission wear so if it's shifting or hunting as GS said leave it in Drive. <br /><br />Other than this, there's no reason you can't tow in overdrive.

 

[sailsmanship]

Re: overdrive or not

I agree with Gstanton also. I had an Expedition and used to do alot of towing. The overdrive light will start flashing when you are taxing the tranny too much, but with any idiot light, when you see it come on it might already have been causing damage.

 

[RubberFrog]

Re: overdrive or not

How heavy is the boat your towing? I'd say under 19' on a flat highway OD is fine. If you hit a hill, take it out of OD. Anything over 19', forget OD.

 

[tommays]

Re: overdrive or not

well it really depends on the RPM your motors turning i have a TOW button thats supposed to do all the thinking<br /><br />BUT what really happens is that it waits long to unlock and to down shift resulting in luging on hills<br /><br />In the real word my motor makes it best power at 2600 RPM which happens in 3rd gear at a nice towing speed.<br /><br />I have tested it and get 11 MPG letting it do its thing in 4th and get 13 MPG letting the motor just do and easy 2400 to 2600 RPM locked up in 3rd<br /><br />tommays

 

[tashasdaddy]

Re: overdrive or not

my GM and Ford manuals say do not use over drive when towing. and you don't have the engine drag when slowing.

 

[BillP]

Re: overdrive or not

It really depends on trailer weight but normally you tow without OD. Like mentioned already, ODs can lug without downshifting. I check lugging by using the instant milage gauge on my car. Hi-way MPG drops a couple of MPGs when in OD so I know it's lugging. I turn off the OD and mgg goes back up. Otherwise it goes down the road without shifting up and down.

 

[Silvertip]

Re: overdrive or not

Ahhhhh the old "to overdrive or not to overdrive question." The only thing about "Never Using Overdrive" regardless who says it, is flat wrong. There is absolutely nothing wrong with towing in overdrive PROVIDED frequent torque converter releases and shifting in and out of overdrive does not occur (these are not the same by the way). Both of those are signals that you should not be using overdrive. Second problem is the infernal TOW button. That changes nothing except it raises the shift points. In my opinion that button should be engaged whether you are towing or not. But then there's this EPA fuel mileage thing. If you have a small, medium or large vehicle and the load is 2/3 or more of the vehicles rated towing capacity you probably should consider NOT using overdrive. Again, it depends on what you tow, where you tow, and what the load is. A tow vehicle with a rear axle ratio of less than 3.55:1 at even half its tow rating probably should not use overdrive. Lot's of factors affect towing. To make a "NEVER" statement is therefore wrong. The manufacturers are again protecting their backsides. For towing there simply is no substitute for cubic inches and gear ratio.

 

[jtexas]

Re: overdrive or not

my explorer manual says to use OD unless it's hunting.

 

[QC]

Re: overdrive or not

I use OD when I tow regardless of the weight, but I watch my tach like a hawk and manually get out of OD whenever I am climbing an extended grade or see/hear it unlock etc.<br /><br />My advice is that if you are diligent and understand the points raised by others above, then stay in OD until one of those conditions exists. If you are more of a turn the key and point the vehicle type of driver, then stay out of OD. Especially if you are towing toward the heavier side of your tow rating. My .02

 

[hisey1]

Re: overdrive or not

wow guys! i guess i've always been a dummy about towing. that is---hook up what i want to tow, make sure it aint gonna come loose, then get it wherever i'm taking it. thanks for all the good info!

 

[glrichards]

Re: overdrive or not

The dealer said not to use OD when towing because gas is cheaper than transmissions

 

[Pony]

Re: overdrive or not

Couldn't have said it better myself QC.

 

[rosco_59]

Re: overdrive or not

 

[DaveM]

Re: overdrive or not

All this talk of locking torque thingies leaves me scratching my head. I always have towed with OD off with my 1994 K1500. And although some said this truck was equipped with a notoriously weak transmission, it had 150K miles on the original engine and original transmission (working perfectly) when I finally sold it last month. Maybe I got lucky or maybe towing with OD off really prolonged the transmission life. I can't say for sure. Whatever it was, I'll do that again instead of trying to save an extra 1 MPG.

 

[JB]

Re: overdrive or not

Every vehicle is different. Do what the Owner's manual tells you to do.

 

[Silvertip]

Re: overdrive or not

Apparently the "no overdrive" skeptics misunderstand why people use overdrive when towing. The answer is really quite simple. "Because they can". The difference in philosophy is that the manuals provide no conditions when NEVER is required. For most, NEVER use OD if you are towing heavy -- that is on the heavy side of the maximum tow rating for your vehicle. If you are towing something under 50% of the maximum tow rating there is no need to run the engine at revs higher than necessary UNLESS the tranny "hunts". If NEVER makes you feel better, don't EVER use OD and your tranny should last forever. Your engine will probably fail sooner however. It all depends on the load you are pulling. If you don't know how to determine when a tranny is "hunting" then stay out of OD.

 

[craze1cars]

Re: overdrive or not

I use overdrive whenever I tow. And I can get away with it because my tow vehicles are significantly oversized for the weights I tow (3/4 ton truck pulling 3,000 lb boat, for example.) Occasionally it downshifts on a steep uphill, and I also pay attention to torque converter lockup and it generally stays locked real nicely. AND I have a tranny temp guage on my rig, so I can monitor heat buildup and know for a fact that everything is fine.<br /><br />Now my buds with base V-8's and little V-6 powered SUV's and towing the same 3,000 lb load? They usually tow without using overdrive. Why? Because their gutless motors are not capable of producing enough torque to prevent transmission hunting and/or torque converter locking/unlocking. So they drop down into 3rd and let the motor spin faster, which helps keep things cool, and this is good.<br /><br />It's been explained here many times already and I'll agree. If your tranny is hunting, don't use OD. If it just very occasionally downshifts due to a solid uphill (not hunting), then you can leave it in OD and let it do it's thing.<br /><br />And if you still don't understand what "hunting" means, or you can't identify if/when your torque converter is locked or not, then you probably shouldn't be towing anything heavy at all.<br /><br />As for what the dealer says? I work closely with MANY dealers. And trust me, very few of them are knowledgeable at all on towing issues. Make your own call.

 

[Silvertip]

Re: overdrive or not

One last comment and I'll bow out of this endless discussion. Generally its the experienced boaters, campers, etc that understand that proper axle ratio selection is crucial when buying a tow vehicle. Base SUVs and pickups today are geared primarily for economy. That means very low engine RPM at cruising speed. So even on slightly hilly terrain, frequent torque converter unlocking occurs and some vehicles even experience frequent OD to direct downshifting. If ordering a new tow vehicle, selecting deeper axle ratios makes a world of difference and in fact can actually improve overall economy since the engine isn't lugging all the time. The benefit is ability to pull hilly terrain, and tow your boat/camper/whatever with far more ease (probably in OD).