Will it hurt the transmission in my '99 OffRoad to run it with the overdrive off for long distances? I drove it a little yesterday with the OD off, and it sure makes the 4.6L more fun. The main reason that I did it and am thinking about doing it some more is to see if my gas mileage goes up. I know that it sounds stupid, but lately I've got 14, 14, 15, and 15.5. The 14 mpg is from city and backroad driving, and this is where I'm wanting to run it without OD. Dad has a '78 F-150 4WD with a 351M and a 4-sp, 3.50 gears, and 33's, and it gets 13-14 steady. When I had my '88 F-150 4WD, 351W and a C6, 3.55 gears and 32's, it got 13 whether I drove it like a boy or an older fella. With the OD on in my '99 and driving in the city or backroads, it seems like the 4.6L is bogging along all of the time. With the OD off, it's got some life to it and the RPM's are where they feel like they should be to an old school guy like me, around 2000 RPM. Still, I don't want to try this if it's going to hurt my transmission.

 

Unlikely to hurt your transmission; also unlikely to improve your mileage.

 

You will be helping your transmission last longer by locking out the OD in some situations. If the "back roads" you're driving are hilly and have many curves and climbs, causing the engine to bog down, or causing many shifts in and out of OD
you're building excessive heat in the tranny. A definate short cut to tranny troubles. And yes, in this type of driving you will get better MPG with no OD.

 

Agree.

The only time OD will get you more mileage is sustained steady driving at 50 mph or faster. It won't hurt to try it. If it works or not, let us know!! Rob

 

It is my opinion (and only and opinion) that engines have a sweet spot and if you are outside of the sweet spot it may be possible to get better MPG and also lugging and engine is never a good thing.

I remember years ago when Datson (now Nisson) built a very very cheap vehicle with a 5 speed that was under powered. Consumer Reports wrote that the vehicle got better MPG in 4th gear than in 5th gear.

So give it a try and let us know.

 

I doubt you will see a milage increase by not using o/d. If you are driving faster than 45 mph for any length of time you will likely see the milage drop.

 

I don't think your mileage will increase by turning it off but I do think it will make your tranny last longer. If you do alot of stop and go city driving, turn it off.

 

My overdrive never kicks in on city driving, that I know of. For improving your mileage, never! From what I understand od just kicks in at faster speeds, so unless your going on the highway, it wont really matter.

 

I don't know what the 4R70W does, but a 4R100 shifts into OD at 41 Mph (min). That puts my truck's engine at about 1200 rpm. ... BTW, we're talking city and backroads, not highway speeds.

 

7700Rob the 4R70W tranny in my 97 shifts into OD at about 40 Mph. Which puts my rpms at about 1100-1200. When driving in the city.

 

I always have the OD off. I hit the button as soon as I put it in gear. The only time I use it is when Im over 65mph....oversized tires dont help it much though.

 

I usually have the OD on in the city. i rarely go faster than 35mph. I read in my Chilton manual that low rpms lug the engine, and can damage the rod bearings by starving the bearings of oil and causing more wear.

 

We have to keep the o/d off in our Crown Vic PI's. The constant stop and go and city driving have burnt up several trannies already. It's one of the first things I do when I hop in. I do the same on my F150 under the same conditions.

 

Here, speed limit in city is mainly 50 kph, so yeah, my overdrive would never kick in!

 

Yeah I always turn my OD off while in the city, mine would kick into OD if I was going 35 and let off of the gass all the way. Then when I hit the pedal it would have to downshift. Should help your trans in town. I can't imagine that you could get better gas economy if going over 50MPH consistently, because your engine will be turning more RPMS= more fuel.