mikez28

I have a '98 Z28 with mods listed in sig. This might be a very dumb question, but what is the purpose of Drive? I don't drive my car much, and usually only take it out on Interstate-95 and just cruise. Generally take it out every two-three weeks and give it a nice run, until the weather warms up alot. Basically, I have only put 700 miles on the car in the last year.

I started driving in Drive on the highway from time to time about two years ago. And recently, I noticed a difference in the transmission when driving like this, but absolutely no problems when I am in Overdrive. I had my mechanic check out my car, and he said I burnt my clutches and asked if I downshift at all. And I don't. My uncle told me that I burnt my clutches because I am driving in Drive on the highway, instead of Overdrive. I had no clue you couldn't drive that way. Is he correct? Are you only supposed to drive in Overdrive on the highway? So basically, what is the Drive gear for? Is it safe to use the Drive gear when running a quarter-mile?

Also, my uncle mentioned that I could have caused some engine damage as well. Could this be possible? I mean, when I do drive like this, I never have the rpm's above 4,000, and no where close to the red line. I have not noticed anything different in regards to the engine, noises, exhaust, things like that.

Long story short, I am getting my transmission completely rebuilt because of it. And trust me, I am never doing this again!

Please give me as much information and imput as possible.

SDB

iTrader: (7)

wont hurt anything in the motor.....
OD is for daily driving ESPECIALLY on the highway, reduces overall gearing (hence the term OVER drive)....
You will get worse gas mileage, and possibly heat up transmission in D instead of OD.

When just driving easy, put it in OD and NEVER EVER shift it yourself. WHen racing at about any speed, pull it back to D (third gear)...when racing top end, you will have to manually shift it OD when at redline in D.

Absolutely no reason to drive around in D instead of OD...actually pretty stupid on the highway! Why would you do that???????

SDB

emarkay

OD means that the tranny is spinning LESS than 1:1 - so your engine is using LESS RPM than if it was 1:1 (what "D" is) Of course you're lower in the powerband, but for cruising, that's perfectly OK, and if you give it gas, it's gonna downshift automatically....

If you wanted a manual - ya should have gotten one!

PS - only time to use lower gears is on hills and towing...

D2REngineering

Seems to me like my transmission works this way:
1 = 1st gear
2 = 2nd gear
D = 3rd gear
[D] = 4th gear with Overdrive kicking in after a few seconds...almost like
a "5th" gear

93LS1RX7

iTrader: (8)

the "5th" gear is probably just the torque converter locking up.

D2REngineering

With the "5th" gear kicking in the RPM's drop about 500-750. Is this consistent with the torrque converter locking up? I'm not real familiar with torque converters.

samz28

yeah put a stall in you'll understand locking up real good or drive a stalled car.

when the trans is slipping at 2500rpm then locks up and drops to 1000 rpm.


thats not really overdrive, but it does lead to more efficiency.

hardly noticeable on a stock (1900) stall