LinkX135

I've looked online for a straight answer but hear different things. I wanted to know if having it on or off affects gas mileage or performance. I drive a lot on the highway and want to see if having it on or off is better for gas mileage. Also wanna see about the city. Thanks in advance.

OnyxCobra

This one is too easy, overdrive greatly increases gas mileage especially on the highway. For normal driving you should always have it on, if the car needs it it'll use it.


Next question.

67mustang302

It's a good idea to leave it off when driving on the lower speed city streets, say under 45-50mph. When it's on if the t/c isn't locked up(below the lock rpm limit for the converter)it can push the crank forward and rub the main thrust bearing excessively, sorta like driving with one foot on the clutch pedal in a manual. Otherwise, yeah, o/d definately improves gas mileage.

nitrous_bob

high gear is usually 1:1 ratio in a mustang

od puts you at .67:1 , just watch how many rpms your tach drops by

and yes in the city you stay out of it , it will cause excess shifting which creates heat and wear

thats the #1 killer of automatics

GreyStang

The owners manual for my buddies F150 says to just leave O/D on all the time except when you have a heavy load in the bed or are towing a trailer.

OnyxCobra

yep, any car u ever drive you just throw in in OD for normal driving.


even at 50mph ur car is gonna want to use overdrive, that is fast enough.

only time i ever take a car out of OD is if i'm going up and down a lot of hills and i don't want it to keep shifting in and out of OD.

nitrous_bob

trust me, unless you have money falling out of your a$$ .......

keep it in "d" for the city

after you spend $2k rebuilding a ford automatic and find out it was all because the od band wore out, contaminated the oil, and toasted everything else....you'll wish you had

67mustang302

+10,000 on o/d OFF in the city, it just causes excessive wear.