Proud new owner of a 08 GT owner. IS there a benefit of having the overdrive on or off? What is the prupose of having this option. Thanks for the help!

 

It's great for highway driving with gas mileage. If your in stop-n-go traffic or can't get over 45 mph for a strech of time I would leave it in D. I live right outside a major city so I drive my current car with a auto trans. in D unless I'm on I95.

 

what exactly does it do?

 

It's just a higher gear ratio, that way your motor revs less going down the highway giving you detter gas millage

 

so will it be faster or slower if i have it on/off?

 

wont be faster or slower. overdrive lets it go into 5th gear when on and doesnt let it go into 5th when off.

 

i thought it wont let you pass 4th gear.. i guess i was wrong lol

 

turning o/d off just shuts down the trans from shifting into 5th. if o/d is on, the tranny will shift up as high as whatever for whatever speed.
if od is off, it will i believe give you some more rpms before shifting (might be wrong) and it will not shift into 5th no matter how fast you are going or what rpm

 

Your mileage will drop, and your top end speed will be reduced. disabling OD just prevents the trans from shifting into 5th which is the only overdriven gear.

I wouldn't even both turning it off even if I was at the strip, you'll never hit speeds where the transmission will want to shift into 5th gear.