Using "Overdrive" when hauling TC?

I too would like a bit of clarification. It's been my understanding that with the OD engaged, or disengaged it makes no difference until you reach a pre-determined speed. When that speed is reached & the OD is engaged, it functions in such a way to enhance fuel economy, but decreases engine RPM & power. So, if your pulling weight & are on flat ground & at highway speed, all is good. If on an incline, up or down, the OD should be disengaged. ??????

Ok, I get the "let the computer do its job" but manufacturers do indicate to disengage when in incline areas towing ???

I have ask two different transmission shop owners who specialize in performance racing and towing transmissions the same question. Both have been in the transmission business over 40 years. I have a 1996 Dodge DSL.

One says turn the OD off when under 55 MPH or 1500 RPM. The reason he gave was the transmission fluid pump does not pump enough fluid for a heavy load when the engine is below 1500 RPM.

The other guy says leave it alone unless it hunts (keeps shifting up and down), and let the computer do its job. The The leave it alone guy did add, when he tows heavy in town, he will shift gears with the stick to keep the engine RPMs up so the transmission will run cooler. He also said it will not hurt the transmission to turn the OD off.

When not loaded, I let the truck computer do its job. When my TC is loaded, on relatively flat ground, I let the computer do its job. When heavy loaded in hills, or leaving a stop going up hill, I use the stick shiftier and OD button.

Wayne

Truck camper with a F-150? Passenger car tires too?

I would be more worried about the tires being overloaded than anything else. But if you are within the GVWR of the truck, you will be fine.

Since 1980, it has been recommended that you lock out overdrive if the transmission is 'Hunting' or going from drive to overdrive and back. Yet if it drops out of overdrive at the start of a hill, and stays out until you are near the top and release the throttle a bit, that is normal.

I would be locking out overdrive on the downhill side though! Anytime that you might need to use the brakes off and on, for a while, then locking out overdrive might prevent you from being required to use the brakes at all. If you find that you need to give it some gas to keep up with traffic, then usually shifting back into overdrive is prudent, and will save fuel. But locking out overdrive will assist in slowing the vehicle on the downhill.

I see so many cars drive down a hill near my work, brake lights on all the way down the hill. I just shift out of overdrive, or with one car shift to gear 3, and never need to touch the brakes. Let the transmission do the work, and save the brakes!

I almost always shift out of overdrive when taking my motorhome off the freeway. It helps slow the RV. Saves the service brakes.

Fred.

If it keeps shifting up and down - lock out the overdrive. Otherwise, let the computer do its job.

My trans expert told me to never put my trans in overdrive unless I'm at freeway speeds, so on flat land I go into overdrive at about 60+, uphill overdrive is off, down hill if not too steep overdrive is on

Like any other situation you need to pay attention. If the transmission starts hunting, lock out of OD. If it is not shifting in/out of OD, leave it alone.

Let the seat of your pants be your guide. If I feel the truck starting to labor, I take it out of OD until I hit the crest. Because it adversely effects gas mileage to have it off, just take it out sparingly as needed.

BTW - Our trip is going to be through the Blue Ridge Parkway and Great Smoky Mountains so I'm assuming there will be some elevation changes to deal with.