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Bad to Disengage Overdrive at High Speeds?

While driving on the highway today I began pondering a general performance question: is it bad to disengage the overdrive when traveling at 35+ mph speeds? Can this cause any extraneous wear and tear on the Transmission?

Thanks for the answers!

Every time your transmission shifts, it causes some wear…It has X number of shifts built into it. Use them anyway you want to…I lock my vehicles out of overdrive until my average speed is over 45 MPH to stop all the unnecessary shifting and “hunting” that occurs when driving in urban traffic between 35-45 mph…

I think that what you describe is exactly what the overdrive kill switch is intended for–to keep the transmission from “hunting” between gears when you want to keep a consistent speed on various grade of hill. That way it stays in one gear rather than shifting up and down (fewer shifts, not more as Caddyman suggests).
On some trucks the overdrive should be locked out while towing or hauling heavy loads.

You do know that the transmission will shift out of overdrive all by itself at high speeds if you press down on the gas quickly enough?
You do no harm by disengaging overdrive at any time or speed. (Of course, there is rarely reason to do so.)

My owner’s manual has given maximum rpm shift point for “down” shifting. That’s essentially what disengaging the OD is. When you “floor” the accelerator and it downshifts automatically, what’s the difference, except in fuel economy and engine wear ? Towing with many vehicles require you to ovoid OD, even at cruising speeds. I disengage it often as others have indicated to retain engine braking in hilly areas at lower cruising speeds. It’s not a problem and probably better for the engine/transmission/brakes etc.
The manual may say so. Some of mine have.

Well, Tardis, I don’t think it is a good idea to lock out the overdrive at high speed as it causes it to shift to 3rd gear and put a jerk in the driveline and send the RPMs way up. And as Caddyman has said, every time a tranny shifts, it causes some wear.