ok here is the story. i bought my truck brand new in 2000 it had 12 miles on it. so i got a few thousand miles on it before i hauled my boat anywhere just to let it break in. well my first trip through the mountains and my transmition was shot completly torn up i had to have a whole new one installed. the dealer told me it was because i didnt turn the overdrive off. so since then i have been towing with overdrive off, but i get terrible milage that way. now that i live in florida where i encounter no mountains do you think that it will be fine to tow with overdirve on. many have told me that if it is just straight highway then it is fine what is your opinion

 

I have always pulled in OD unless in heavy hills or the mountains. If it doesn't hunt in and out of OD you will be fine.

Denny

 

i agree with denny, your fine unless you get hills and mountains. another scenereo where its a good idea to turn the o/d off is in city driving where your gonna hit a lot of stop and go driving, or heavy traffic on the expressway.

 

If your transmission is "searching", or shifting between 3rd and 4th (OD) gear constantly, it'll build up heat and wear out MUCH faster than if it was pulling the same load in a single gear, be that 3rd or be it 4th. The damage is caused by excessive shifting, not by pulling in and of itself.

The myth that you can't tow in overdrive is just that, a myth. If your transmission isn't searching, you can (and should) tow in normal drive, using all gears avalible. If it starts to struggle and shift, turn off overdrive and keep the transmission cooler.

Its also a myth that you will burn much more fuel in 3rd than you do at the same speed in 4th. The difference is actually far less than you might think. The total load is what eats fuel, not RPMs alone. The engine is doing the same amount of work pulling in third as it is in fourth. Sometimes, pulling heavy loads, you may actually be more efficient in third gear. So select your gear based on what the engine tells you, rather than what you think it wants to do

I've towed my 7000lbs gooseneck trailer with my F150 for 5000 miles now plus all the other trailers I haul (I was pulling 50 miles a day for the past two months), and its still on the original transmission with 130k miles on it with no symptoms of trouble. Much of the time I turn the OD off, but for more than half of the miles were driven in fourth gear.

 

i think with the f150 you have to turn off the overdrive, but the superdutys don't. something about the band for the overdrive on the 150's. if you do a search this has come up before and a tranny engineer said what the problem is.