Originally posted by hetfield:
Originally posted by Dark Sport:
From what i understand, overdirve is just a higher gear that the car goes into saving you gas. unless you need to accelerate really fast i'd keep it on.
Yup. O/D is 4th gear. I turn it off in cases where the computer doesn't know which gear it wants to be in, like while accelerating on a steady incline, since the constant shifting probably isn't good for the valve body. Leaving it off for extended periods of time will just cause undue wear and tear on your tranny and burn gas quicker.
Actually on most, if not all automatic transmissions, when you push the O/D button it's not another gear.
Although you are changing gear ratios, the reason for the change has to do with lock or unlock torque converter.
When the TC is unlocked it will act as another gear ratio.
If you have your shifter in drive you should get 4th gear with a 4 speed auto trans regardless O/D on or off.
In that the TC is a viscous couple, its not efficient and you get better fuel economy with it locked when traveling at constant speeds.
For fast acceleration and starts from a stand still you want the TC unlocked to gain from the advantage of the extra gear ratio.
So for better fuel economy leave the O/D active.
When you want to accelerate very fast turn it off and then back on once you get to your desired cruise speed.
Anthony B. Davis
2Deep2 Silver SVT
2002 IASCA SQ Ult Ama 601+ World Champion runner up
2002 SLAP dBQ Champion 
2000 USAC SQ World Champion
2002 USACi SQ World Champion
| 
