Overdrive???????????

Question

The specs for my car [2000 hyundai tiburon] say 4 spd auto with overdrive. does this mean it has 4 gears and overdrive acts as 5th gear? or does it mean that 4th gear acts as overdrive.

Please help. I got the transmission replaced and I am trying to figure out what is wrong with it.

I am desperate. The dealership that replaced the transmission is insisting its fine, but it runs high rpms and eats gas.

please help

Answer 1

That "with overdrive" bit is them just blowing smoke to make the car sound better.

What it means is that fourth gear is an overdrive gear.  All that means is that the output shaft of the tranny is turning faster than the input shaft - if the engine is spinning at 1000rpm, then your tranny's output is turning faster, maybe as much as 30% aster.

Does your shifter have a separate button on it that turns the overdrive on and off?  When cruising in gear at a speed that should definitely have the tranny in its top gear, does operating that button make anything change?  If not, when they reinstalled the tranny they forgot to hook that wire up.  It should be a simple fix, and it should definitely be on them to do it.

If your car doesn't have the button, I'm sorry but I don't have much else to suggest.  But if the dealer worked on it and now it isn't working right, they should be the ones to make it right.

You can do the math for your car, the transmission ratios and the final drive ratio to come up with how fast the engine should be turning at speed for each gear.  Work that out and you can just show the techs a chart of engine revs vs. road speed for each gear; when it shows that your car is doing too many revs, they won't have much argument beyond "yup, it isn't shifting up.  We'll fix that."

Okay, just saw your addendum.  There's a possibility they put in the wrong tranny, or one with the wrong final drive ratio.  Get the specs for the tranny they installed and compare them with the specs for what came out of your car.

At least, that's what they ought to do.

Good luck.

Answer 2

It sounds like they replaced it with a non overdrive trans (if they even exist) or the one they put in is not working correctly.  If it isn't hooked up right the computer may not let the trans torque converter lock-up and it may prohibit from using overdrive.  Have them check the overdrive electrical connections, they may have left it disconnected.  

Answer 3

turn on overdrive