I have a 97 4.6L 4x4 extended cab with a 175,000k. I had the truck about a year now and I just noticed that the OD light doesn't work. When I press the button nothing happens. That made me think that the Over Drive might not be working at all. I took it out on the highway, at around 60-70mph hit the button and nothing. The tranny didn't shift at all. It also dosen't feel like the OD is engaging. I just had my mechanic due the plugs, wires, and coil packs and told him about the OD issue. He took it for a ride and agreed that it dosen't seem to have OD at all. I didn't really have the $$$ to have him look into it more. Does anyone have an idea on what it might be?

 

Did you check the fuse for it ?

CJB ( aka Central Junction Box / Cab fuse panel ) fuse # 29

If you install a new fuse, and it blows when you try using it, check or chaffed wires where they come out of the bottom of the shift lever.

 

You should be able to tell the shifts. Accelerate onto the highway at moderate throttle and feel each shift, watch your tach. The tach should drop at each shift as well as you feel it shift. Start out stopped so you make sure you are in 1st gear and then give it throttle. Count the shifts, 1-2, 2-3, 3-4 (4 is OD).

Also what is your rpms at around 70 mph? 3000-ish rpms is about right for 3rd gear, 2200-ish is about right for OD. Depends on gear ratio and tire size of course, but there is a significant difference. If you don't have OD working it will be winding pretty good on the highway. Your mileage will also be down if crusing in 3rd vs OD.

 

I will check the fuse soon as I'm done writing this thanks for the heads up. Sometimes I forget to think of the simple things like fuses.

My tire size is stock and stock gears to what ever they are. I didn't check each gear shift, thanks for spelling it out like you did that makes it easy for me to check. I know the RPM's are just about 2,000 @ 70mph and around 2,300 @ 75mph. So from what you said my OD probably works. I will do the actual test on my way to work tomorrow.

Thanks for the help!!!

 

Evil

Actually the switch disables the OD. You use it when hauling to stop OD from engaging and potentially harming your trans. If it does nothing, then you cannot disable OD. By default your OD is working.

 

yep it is definitely working I just can't shut it off. I will check the fuse when I'm off work.

 

Those switches do go bad on a regular basis. It might just be that the switch has bit the dust.

Darrin

 

I think you nailed it. The fuse is ok, and the Over Drive seems to be working fine. At 70mph it's @ 1,900RPM's. Any idea on how much a switch cost? Do I have to buy it from Ford?

 

Dorman makes a switch. If that doesn't solve it then my guess would be broken wires at the shift lever (which was my problem). In that case you have to replace the assembly, I think it's like $60 from FoMoCo

 

I think that is the way I have to go. The fuse is good and everything else works ok. I'll check into that switch soon as I can muster up some $$$ without the wife seeing.
Thx.