What is overdrive, and when should it be put on or off?

 

Overdrive is like an extra gear in the transmission. Once asteady speed is reached then the overdrive kicks in lowering the engine rpm. In turn decreasing your fuel consumption while maintaining your speed improving your gas mileage. You should never tow with your overdrive on. Have read articles that aslo say not to run in traffic(city driving) while on. Dont know about that one. I am sure someone on here knows more about trannys than I. I believe it only works once you are in the final gear.

Short and sweet version of how it works. Pretty sure a long version is on its way.

 

there was a thread on this about a month or so ago here is what it said:

The button disables the overdrive operation when you push it in and the light comes on.

Normally the trans shifts intooverdrive on it own at around 60km/hr

go for a drive on the highway once you get up to cruising speed push the button on and off. you should feel the trans shift back and forth between 3rd and 4th gear (overdrive) and you engine RPMs will go up and down a few 100

 

Overdrive is a "gear" in your tranny where the ratio is less than 1.0.

Its hard for me to explain... umm

I dont know waht the gear ratios in the trannys are in these trucks, but say 1st gear is 3.5, that means the driveshaft will spin 3.5 times per one revolution of the engine... If the ratio were 1.0 it would be direct drive and the engine and driveshaft would spin at the same speed.

Engine tourque falls of extremely fast in overdrive, thats why when your on the highway in overdrive it really doesnt feel like there is any power there at all.

You should have overdrive off when towing things, and I usually turn mine off when im under 50mph and will be stoping and going alot... the truck has a little bit more engine breaking and it shifts sooner and at better times with it off. Kind of liek a "tow/haul" mode like the chevys.

 

So in general, should I just have it on? I mainly do city driving.

 

Right...Leave it on, unless your doing "heavy towing", which i dont think you will be with a truck of that size lift. But if you do tow, and its a good size load, take her out of overdrive so you dont overheat your transmission. By taking it out it helps the transmission stay in certain gears in the transmission, oppose to it hunting for gears. You will notice that the engine RPM's will be higher than normal and your gas will suck, but u will save the tranny ect.

 

Ahhh I see. It all makes sense to me now. Well heres just one more question. When I am racing somebody at a light, should I take it out of overdrive to increase maximum torque?

 

I suppose you could, but i bet there would be minimal notice in the race, maybe just a longer more outstretched first gear ect...I wouldnt, seems like extra wear to ur tranny to be doing that

 

Some guys that drag manually shift from the 1, 2, and D gears in an automatic. If you do this, you can get the RPM's higher in each gear and get a bit of a "launch" or "lunge" when you drop it to the next gear. I don't do it personally, as I can't imagine that's good for the tranny to pop into gear at 5000 RPM's

 

don't do that
haha
it is okay, well at least better, to turn overdrive off, start in (1), mash it, shift to (2), and then to (D)
three speed tranny!
when in (D) try to let off some when the actual MPH is getting up there to about 60-65 - allows Torque converter to lock up instead of just slipping 1000 RPMs and making a huge heat source in tranny...

dont try to make your launches like a trasnbrake... dont mash it, and slam it into drive
cause one of the next times you do that... you are going to move anymore and just bounce off the rev-limiter... haha
you will blow out the seals...

overdrive is when a big gear is driving a small gear
highway driving and fuel economy...

it is good/okay to turn off for City driving

overdrive with Torque converter lock-up occurs anywhere from 38-60 MPH depending on throttle
averages about 45 mph