JPB

What are the benefits of driving with O/D on or off in town and on hwy? 2012 JKU automatic, 35" tires, 3.73 gears. Trying to improve gas mileage really until I regear. right now i'm getting about 13.2-13.9 mpg in town and about 14.2-15 hwy.

Can someone explain how driving with it on or off works?

Huggerls1

There is an overdrive button in the 12? Never seen mine. Your mileage seems low. I got that when I was towing a trailer across the country with 35s same gear ratio

JK-Ford

O.D. OFF - Gas milage goes \/ \/ \/
O.D. ON - Gas milage goes /\ /\ /\

You should only turn your OD OFF when towing. Or when your transmission is having a hard time staying in OD because of headwind, steep incline, heavy load inside vehicle, or someone is running BIG tires.

JPB

well there is no "button" but you can manually take it out of OD with the + and - (manual shift) on the shifter

yea still trying to get better gas mileage. I'm not expecting 19 or 20 just better than i'm getting now

Ryan0260

It will help to keep it off as far as power when running bigger tires to compensate for not having low enough gears. It will hurt the fuel economy some, but will help from bogging the engine down, especially when towing or going up hills

jk.bushwacker

i've also found turning off O/D in 4lo is really handy too

BlackRockBurner

Elevation; elevation changes; driving habits; headwind; on top of 35s will make your transmission hunt for gears. If your rig is constantly dropping gears, it may be a good thing to turn over drive off. Sure, you will not get the benefit of lower rpms, but your tranny will be happy by not shifting every 30 seconds.

JPB

thanks for all replies!!