I have noticed something interesting with my 96 auto SE. I normally drive my car around the city with the o/d button OFF. Since I do not drive at a high rate of speed around town there is no reason to go into 4th gear. Plus I like having the extra torque in case I want to KILL a Ferrari (insert laughter here). But when I get on the freeway, I immedialty put the o/d button on the ON position. The other day I had forgotten to turn the o/d ON. So I was in 3rd gear at about 3500 RPM and still accelarating slowley. I pushed the o/d button to the ON position and I immediatly got and extra boost of torque and the RPM jumped 500 RPM. I did not push the accelerator down anymore then it already was. I tried this again after I had exited and got in back on the fereway and got the same results. Anybody have an explaination as to why this happens?

 

O/D off locks the torque converter off. o/d on allows the torque converter to kick in.

 

So does this mean that if I keep the o/d button on the ON position I will have more torque in every gear?

 

Not quite. The OD button permits the TCU to shift into 4th gear (overdrive), as well as lock up the torque converter (a mechanical coupling, like a manual transmission) in 4th gear. Turning off OD will only allow access to three forward gears, and I believe the torque converter can lock up in 3rd gear as well.

There is no such thing as "turning off the torque converter." It is always spinning and moving fluid whenever you are in gear.

As for the 500 RPM increase...I cannot explain that. If you are accelerating lightly at freeway speeds, turning on OD should drop you into 4th gear immediately. Perhaps you are referring to the slight RPM increase during shifts. This is a normal feature, as the engine retards timing slightly to smooth out the shift. But I don't recall it being 500 RPM, and it's like a fraction of second, hardly long enough to help the car accelerate.

 

When I turn OD ON, my RPMs decrease. I'm guessing cause the car shifts into fourth gear.

How would turning OD ON make your RPMs jump?

 

The only way to explain it is that when I am accelarating slowley, not hammering down the accelarator, and I turn on the o/d the RPM jumps. Kind of like going in an extra gear between third & fourth. Hard to put into words, just try it under the conditions I described.

 

I have a question regarding the O/D button. Do you think it is better to keep the O/D on or off at the track ,which one will give you better performance on/off i was just wondering.

thanks
cliff

 

Whenever I turn on the o/d, my rpm's decrease. When I turn off the o/d, my rpm's increase.

 

Is that an echo I hear?

 

http://forums.maxima.org/showthread.php?threadid=63439

http://forums.maxima.org/showthread....5&pagenumber=2

 

Thanks for the info on the post. I should have researched this before I asked this question.

 

I'm not too hip on all the internals of an automatic, but I do know that the clutch bands for 3rd gear isn't all that great. Sometimes when the car shifts between 2nd to 3rd, there is a spike in RPMs before it settles into the next higher gear. Maybe the same thing can happen going into 4th gear. I read about this on LevelTen's website.. it was one of their FAQs.

 

eric i thought it shifts to 3rd gear.

most of the time, i feel like od on/ off dont really matters.

 

It's 4th...on your gear shift, you see three forward gears 1,2,and D. "D" is actually 3rd gear. With you turn OD on, you let the computer shift into 4th gear.

OD on: 4th gear available
OD off: locks out 4th gear, only 1,2,3rd gears available

Don't confuse locking out 4th gear (OD off) with "locking up" 4th gear, which is what the torque converter does to enhance fuel economy.

 

how interesting