OVERDRIVE OR NOT

i've always been told (and it seems the owner's manual confirms this) that you only need to lock out od when the tranny is shifting excessively to find the right gear... that being said i've never towed in od because i've never towed in flat areas... even a minor grade seems to force me to down shift. locking out od would likely only hurt your gas mileage (and that may not even be the case if you your running close to where the tranny would down shift but doesn't) if anything where as excessive shifting could cause the tranny to over heat

if you want to use od, try it out... you'll know pretty quickly if you're TV is shifting a lot. if you don't want to use it, it certianly wouldn't hurt anything to lock it out