Overdrive on or off?

I would be in overdrive unless it starts to downshift frequently. What is frequently? Make it 15 minutes or less.

a mechanic told me if it has over drive factory installed it is OK to use it when on the open road. that's why it is there. like the above post states, if the tranny is searching for gears, it is time to turn it off and down shift. when the road is level or going down a hill, turn it back on.

Is your button labeled "O/D Off" or "Tow/Haul"?

If you have an "O/D Off" button, it's an older chassis with the four speed transmission and the button simply locks out the fourth (overdrive) gear. This can be useful when driving through areas of rolling hills, etc. You can also make it kick out of overdrive by pushing the accelerator down far enough to make it downshift.

If it's labeled "Tow/Haul," you have a newer five or six speed transmission, and the button does not disable overdrive. It instead alters the shift logic some to optimize it for heavier loads--tending to stay in lower gears longer, downshift for engine braking, and avoiding unlocking the torque converter so as to keep the transmission temperatures cooler, perhaps among other things. Since a class C motorhome is a large load for the chassis, it's perfectly reasonable to leave tow/haul engaged all the time. It's especially helpful in hilly or mountainous areas.

My answer was going to be, "depends", but it looks like it's been answered pretty well.

I checked the OP`s sig, thy have a 98 E350 chassis. so with that I would leave O/D on and only lock it out if it shifts in and out of O/D frequently.

Dick_B wrote:
I would be in overdrive unless it starts to downshift frequently. What is frequently? Make it 15 minutes or less.

The manuals say things like "not in hilly country", "not if towing" and "Not in bad weather" as a general rule.

But the advice is the best advice.. If it is constantly "Hunting" for the right gear (Shifting frequently) turn it off. but if it's shifting into Overdrive and staying there for miles and miles and miles and miles (how far CSI-Cyber adn the WHO can see) Well... (yes that is a joke), Well then engage it. and leave it engaged, Makes a major difference in MPG on my Class A.

wa8yxm wrote:

Dick_B wrote:
I would be in overdrive unless it starts to downshift frequently. What is frequently? Make it 15 minutes or less.

The manuals say things like "not in hilly country", "not if towing" and "Not in bad weather" as a general rule.

But the advice is the best advice.. If it is constantly "Hunting" for the right gear (Shifting frequently) turn it off. but if it's shifting into Overdrive and staying there for miles and miles and miles and miles (how far CSI-Cyber adn the WHO can see) Well... (yes that is a joke), Well then engage it. and leave it engaged, Makes a major difference in MPG on my Class A.

Here's a ham radio guy showing his age! He remembers the band "The Who" singing "I can see for miles and miles.....". I think I read about that in history class. (or maybe not) :B

Also you can have the PCM reprogrammed to provide optimal towing/loaded shift strategy. I did just that with my V-10 Excursion and it dramatically changed how the truck performed with my 9200lb TT.

Check out 5star tuning, they have a very good reputation with the triton motors and towing. With them it's not all about power but the overall performance for what you want it to do!

Simple. Leave OD on if the trans is holding that gear. Turn it off if keeps downshifting or even unlocking the torque converter.
In hilly terrain, just lock it out. Triton engines like to rev and your transmission and brakes will thank you for it.

Off is fine too if it just drives better.