When i am not towing should my overdrive be on or off?

 

off unless its a very light load.

 

the question was when NOT towing.

So the OD should be ON (no OD-off light in the dash)

ps.: it's ON by default when you start the truck.

 

Ha good call. Maybe should have worded the title a bit different. But yeah, leave it on when you not towing, shut it off while towing/ carrying heavy loads.

 

If i am towing my boat on the highway should i turn off my 0D?

 

Yes. Otherwise you'll shift erratically between TC lock/unlock - wear out the 4th gear pretty quick. That, or you'll bog like an SOB on a hill and lose speed - look at it like this, if you are towing something, cargo trailer, boat, whatever - that weighs more than 1000 lbs then turn it off. Is it necessary? No, but if you're like me and HATE losing speed on hills and can't resist the urge to exceed the posted limit by 5-9mph simply because a line of cars will form behind you if you don't, then do yourself a favor, skip the constant shifting and just turn it off.

The retarded TC tune on these trucks doesn't unlock until you're damn near full throttle in 4th anyway. So you're chugging along at 50 in a 55 losing speed up a hill at 1500 rpm and it won't shift down, give it more gas (almost floored) then it will shoot up to 3500 rpm in 3rd instead of simple unlocking up to 2500 to make it over the hill. Truly, truly annoying.