what is overdrive mode for?

[deuce07]

i tried searching.. i went through a couple pages but coudln't find any answer..

i was wondering what exactly is Overdrive mode for? if it shut it off, would it increase MPG?

i tried switching between OD and OD off, noticed that OD has more pull and haul, i like OD off because its alot smoother and relax..

please let me know....

 

[diego]

overdrive is your cruising gear helps you get better mpg

 

[deuce07]

thanks for quick response.. =/ i feel that in OD mode, when i gas, its stronger.. and when OD is off, it feels smoother..

 

[diego]

Its like a 5 speed bike kinda when you go to the bigger gear you just cruise with out pedaling as fast as the small gears

 

[manaen]

OD mode also locks up the torque converter so there is no slip therefore not wasting any power. Also the tranny itself, as stated, will run in a higher gear for cruising on the highway.

If you tow anything heavy make sure you disable OD
If you are climbing a large mountain turn off OD
If you have a heavy load on long slopes you may need to turn off OD

OD should be the default mode that your truck starts in, that's ok. However if you find the truck wants to shift up and down a lot then you may want to disable OD until you get to flatter ground / better conditions.

Why? you ask...
because you can quickly over heat the OD bands in the transmission if you are feeding it a lot of torque (AKA heavy throttle) for long periods. The OD Band will try to keep the tranny from slipping and the engine will push it hard with torque. It's best to sacrifice a few MPG and save yourself tranny repair costs. You just need to identify those situations when it is best to disable OD.

 

[Jon94]

Overdrive is the 5th gear in the transmission. When you accelerate from a stop, the trans is in 1st gear. As you go faster, it shifts to 2nd gear, then 3rd gear, 4th gear, and finally 5th gear which is called the "overdrive" gear because in this gear, the driveshaft actually spins faster than the engine. This lets the engine run nice and slowly while you're on the highway, which saves gas. For fun, next time you're going about 55 mph, press the buton and see what happens. With OD off, the engine spins much faster.

As was stated before, if you're hauling something heavy, keep OD off. It puts a lot less stress on the transmission.

 

[DavidEBSmith]

More than you ever needed to know about overdrive:

http://en.wikipedia.org/wiki/Overdrive_(mechanics)