OD or not to OD

Yes, and that's by design. With OD off your fuel economy will suffer greatly.

About the only time I think I might consider turning OD off would be if I was towing something over hilly or mountainous terrain.

I agree. Thats the way they make them to run. I never turn mine off unless pulling.

I pretty much follow the owner's manual on that one.. I seem to remember that it recommended locking out OD if you were in a lot of traffic and staying under 30 mpg.. locking OD out stops a lot of hunting... shifting down every time that you hit the gas, then back up as soon as you lift your foot at all..

I also lock out od on mountain roads where you're not going to be going over about 40.. it feels like I have a bit more control, (like down shifting a stick), and prevents it from shifting up as you take your foot off the accelerator going into a turn.. YMMV

mac

Please remove splinters before emailing

It will not hurt a thing and it not really a bad idea around town or towing as they will be less hunting through gears. On a flat hiway cruise with no load you might lose a few MPG but there is a lot of other varibles that determine how big the loss is if at all in some cases.

How did we survive for many years without OD??? In a big SUV it will not make that much difference, maybe a few MPG at most and if it has taller ratios to begine with and oversized rubber, MPG will likely improve.

No problem, unless you are going up or down a long hill or mountain.

JAM