Obviously I didn't reply to that thread. Sorry for the mis-information.


Umm, I don't know the exact reason for that name. But it puts your car in the highest gear when you are cruising so your RPM's are lower, resulting in better gas milage. So it kinda 'over drives', if you catch my drift.

O/D for a manual does the same thing as it does for an auto. Thats why on a 5 speed the 5th gear is O/D, and on a 6 speed the 6th or 5th and 6th are overdrive.

They do make 5 speed autos now. They are the only auto you can get for a 05+ mustang. Alot of cars have them. Mercedes-Benz even uses 7 speed autos on some cars.

And you're monte carlo doesn't pull hard, it's your imagination. Next time you imagine that remember, it's a monte. You can't go fast. lol. J/k about that part. I don't know why your monte does that.


To sum it up. Pretty much, yes.

 

Overdrive comes from the gear ratio. In a standard transmission, 4th gear generally sets a 1:1 ration between engine and transmission output. The 5th gear in a standard is the "overdrive" because the engine turns at a slower speed than the transmission output shaft. In the Automatic, the overdrive is the same thing. It lowers the gear ratio to below 1:1, usually .85 or so. What this does is lower the engine rpm for a given speed (like highway driving) and therefore reduces friction and saves fuel.

Driving with it on or off is up to you. if you have it on and stomp on it, it will be like having it in 5th gear and stomping on it. The transmission will then sense the load and shift down to raise the ratio. This takes a second or so. If you are racing, turn it off, it does you no good, except slows the response because it needs to downshift for torque. Also, you might turn it off if you are cruising and it continuously shifts up and down, such as climbing a long hill in cruise control. It might downshift to accelerate, then upshift and slow down, then down shift, and so on...

 

It's called overdrive because the gear ratio for that gear is less than 1.0. For the six speed cobras, both fifth and sixth gears are overdrive gears because their ratios are .65 and .5 respectively. I couldn't explain the whole logic, but why do you think they are called Underdrive Pullies? It changes the ratio between the pullies so that the accessories spin slower, having less parasitic drain of horsepower. Gear ratios above 1.0 are underdriven, and ratios below 1.0 are overdriven.

Just a thought on the logic, probably called over drive because for every 1 turn of the engine through the transmission, more than one revolution comes out to the driveshaft. Sorry if that doesn't make much more sense, I'm pretty tired.

 

It has 300hp.

 

you had asked if u can turn it off and cruise at 4k+ rpms to hear ur exhaust...everyone said that was a bad idea

 

hahahaha, that's a totally different question.

 

Some of these posts should be a general tech sticky.

 

What I read was .82 and .63 (or there abouts).

 

Thats all we need. More sitckies. [&:]

 

Eh I'm not sure, I grabbed the highest ratios from the list on Tremec's site. There's about 15-20 different T-56's that Tremec makes, they have all the ratios listed on their site. I am fairly positive on the TR3650 being a .68 fifth gear, so I would hope the sixth on the T-56's would be a bit higher.