Towing -- Overdrive On or Off?

jlrray · 07-15-2008, 08:47 PM

When you guys tow your trailers with your SMB, do you turn OFF the overdrive to achieve better mileage?

I guess I should have posted this to the towing section.. oops
JOe

**BroncoHauler** · 07-15-2008, 10:03 PM

I usually leave my O/D on, provided the terrain is fairly flat. In hilly terrain, if you find your transmission hunting up and down for the right gear, I would take the O/D off.

Herb

jage · 07-15-2008, 11:04 PM

I only take the OD off it the tranny is hunting the right gear... e.g. ditto what Herb said.

oh and *poof*

**daveb** · 07-16-2008, 12:22 AM

Same here. long downhill and flat runs are in OD. I would think a heavy trailer might be different but my SMB trailer is not a problem.
DaveB

Ford_6L_E350 · 07-16-2008, 09:05 AM

It would depend on the trailer.

With a heavy trailer (6000#) I would probably leave the OD off. A little more power going up and a little more engine braking coming down.

With my little SMB Rockcrawler trailer (2000#) I drive the same as without the trailer.

Mike

deminimis · 07-28-2008, 01:38 PM

This was discussed heavily in regards to full size chevs a while back (better trans too in my opinion) on a different site. Insofar as Chevs, it was a no-no to trailer while in OD unless flat or downhill or a very light trailer. Ok, we all have Fords, so perhaps not as relevant, but I turn off the OD whenever the trans is searching, even without a trailer (some long uphill grades 'round these parts). When hauling a heavy trailer, OD remains off for me, unless I'm out on the flat interstate with the wind at my back. When using a lighter trailer (motorcycle trailer, for example), I go back to the searching rule of thumb.

yvrr · 07-29-2008, 08:59 AM

If a transmission is continually shifting in and out of OD, it will cause it to heat up which can eventually lead to failure. It has been suggested that it is best to take it out of OD as soon as you get to some hilly terrain regardless if you are towing or not. The same advice would apply anywhere if you are towing...

BC · 08-08-2008, 11:45 AM

I'm with deminimis on this one, judicious use and awareness, on or off depending on grade, wind, conditions, load, etc. So its both.

I occassionally tow a small utility trailer and also a 15-ft Boston Whaler that probably only weighs about 1500lbs w/trailer. Neither is super heavy by any means. But I am constantly using OD to modulate, never allowing rpms to drop too low on climbs and also using it for speed control on downhills. So its kinda on and off, diligence required, watch the Tach and just common sense sorta thing. On when climbing grades, off on flats, on on downhills if you need it, and so on.

cellularSTEVE · 08-08-2008, 01:48 PM

Quote:

Originally Posted by BC

On when climbing grades, off on flats, on on downhills if you need it, and so on.

Maybe I am thinking of it differently but isn't it the opposite? Shouldn't it be:
OD-OFF when climbing grades, OD-ON on flats, OD-OFF on downhills if you need it.

Maybe we just have the terminology different?
When the OD is OFF it is a lower gear (revs higher).

steve

**daveb** · 08-09-2008, 11:31 AM

Quote:

Originally Posted by cellularSTEVE

Quote:

Originally Posted by BC

On when climbing grades, off on flats, on on downhills if you need it, and so on.

Maybe I am thinking of it differently but isn't it the opposite? Shouldn't it be:
OD-OFF when climbing grades, OD-ON on flats, OD-OFF on downhills if you need it.

Maybe we just have the terminology different?
When the OD is OFF it is a lower gear (revs higher).

steve

Ya you're correct. But on a down hill grade many times I will turn off the OD to help brake. On a smooth long slight downhill grade I leave it on to keep the RPM's low and save fuel. Now according to my scan gauge, (depending on the grade and RPM's), the fuel is basically shut off while engine is braking so at times it's better to leave the OD off going downhill which allows the higher RPM's to cause the trany and motor to go into a engine brake mode and turn off the fuel. Sometimes the RPM's are not high enough to let the engine go into the brake mode and shifting into second will do it but I don't constantly shift in and out to save a penny when a trany rebuild is such a high cost. I think that if the trany is constantly shifting in and out (or seeking) that's bad and as Jack said, causing heat and unecessay wear. That's why you need to leave the OD off in typical in-town driving. Why let it shilt through all the gears and into OD when in 400 feet your going to stop and do it all over again? On my 2000+ mile journey to Colorado, most of it was flat and my SMB trailer wasn't so heavy as to cause seeking and on those flats I kept the OD on. If I hit high winds or hills I turned it off. If I don't know the terrain of the hills ahead of me I leave it off. In Colorado I drove in and out of the Poudre river canyon several times. I flew past Jage (two of the three SMB's I saw on the whole trip) "in" OD because I knew it was a slight very long downhill grade that wouldn't allow me to engine brake with the OD off.
(sorry Jage my picture of you didn't come out. I'll never set my camera on top of an ice chest full of water again!)
DaveB