I have a strange one. Ok well I bought my 89 F150, 302 v8 4wd with an automatic transmission about a week ago and the speedometer doesnt work. Ok well I first thought the cable or gear. Well I hooked a drill up to the gear and the speedometer in the cab worked. Ok then I looked at the gear and it doesn't look very worn at all. I put it back together and went out for a ride and realized when I put the truck in reverse the speedometer goes in the negative direction the faster I go the further it goes till it cant go anyfurther. and when I go forward it wont go in the positive direction. well it seems to me that it should be the other way around lol. I know a speedometer isnt supposed to go in the negative direction like that its suppose to stop just like it does when I try to go forward. why is it doing that its like it will read it when I go backwards but not forwards plz help.

 

that sounds cool.

 

No idea on that one. sounds interesting

 

That's normal, it sounds like you may have the wrong gear in the trans. Get in another car with a cable controlled speedo and back up, it'll do the same thing. It sounds like a bad speedo to me though. It should work going forward. You might want to remove the cluster and drive it down the driveway to make sure that the cable is indeed turning when you're moving forward.

 

well I know its not the cable though and I think its not the speedo cause like I said I hooked a drill up to it and it worked fine going forward and in reverse. So the speedo has to be good?!?! right??? And the gear in the transfercase has to be working for the speedo to work in reverse.

 

Does anyone have any other ideas??

 

Didn't anyone watch Ferris Buelers Day Off .... all the cable operated ones I know of did go back some unless there was a pin to keep the needle there, but the Odo would go back. I'm with the guys that the gear is wrong, but I don't know what the insides of these trannies look like.

 

I have never seen a vehicle that would reverse the Odometer when driving backwards. It would make no sense for it to. As in Ferris Bueler's Day Off, it doesn't work that way.

As far as the problem of it going backwards and not forwards, I'm not to sure if it would be the gear at the end of the cable. With the improper amount of teeth or an opposite direction curve, your gear would either not spin, tell you the wrong speed, or be inconsistant. I'm wondering if there may be an issue inside the transmition. Of course I may be way off. Your best bet would be to try and find out what gear your supposed to have and replace it. It's only a few bucks and if that is not it, your not out a lot of money or time.

I think it's deffinatly on the gear/transmission end if you used a drill and your speedo works.

 

all the fords i've had do that. except the digital cluster in my 92 marquis. just not very often ya back up a tenth of a mile

 

Actually in reverse the speedo will work, but the odometer does not. So it doesn't work, just like in the movie, remember it didn't work causing Cameron to get upset and kicking the car out the window. Just because it worked with a drill, and works in reverse doesn't mean the transmission is engaging the gear when in forward motion.

 

I had an '86 Toyota Camery that if you backed up would roll the odo backwards. That's how I got my picture of the odo at 300 000 km that was my favorite little beater I've ever had, couldn't kill it. And Ferris Buler's day off is a classic movie.

 

Sounds to me like somebody put the speedo gear on backwards on the tailshaft?

 

Your truck is not called Christine by any chance is it?

 

If it is Christine .... drive if for a few 100000 miles and then you will have a new truck!