bobcat8258

I recently purchased a 1989 F150, 4X4, 4.9L, 4 speed manual. My speedometer isn't working. If I spin the cable at the transfer case, the speedo moves, but when I screw the piece back into the transfer case it doesn't work. Is there a gear of some sort insdie of the tranfer case that could be casuing the issue. Also, any ideas of how to repair. I have dual fuel tanks, but my gauge isn't working, it constantly reads way past full, what is causing this.

5Rangers

The speedo drive gear on the transmission output shaft is worn. You have to pull the driveshaft and the transfer case tailshaft housing to replace it. The gear is held in place on the output shaft with a retainer clip and a ball bearing. Easy peasy.. you need a #50 torx driver for the t case screws. If you have any oil leakage from the housing to driveshaft there is a bushing and seal on the back that's easily replaced as well.

Does your fuel level show past full on both tanks?

Aqua_Man

I have an issue like this but when i'm driving, it doesn't move until i hit about 30 or so and then it just bounces.

5Rangers

What year you truck? If it has mechanical speedo troubleshoot the same way. Pull the gear out of the tailshaft housing and turn the cable to see if the speedo responds. If you have a drill, take the driven gear off, attach the cable to the drill and turn it slowly at first to make sure you going the right way. See is the speedo is solidly indicating. If not the problem is the cable or the speedo head. If it reads good then you driven and drive gear for the speedo is probably toast.

Aqua_Man

its an 89 with a 302 (if that matters). Im not sure if its mechanical or not.

5Rangers

Its mechanical..A drive gear, driven gear, cable and speedo head. Either or both of the gears could be worn or broken, the cable could be broken or something wrong with the head itself.

bobcat8258

Thanks to all for your feedback on the speedo issue. Yes my fuel guage reads past full on both tanks.

Aqua_Man

Alright. Well I guess I have a project for Saturday.

5Rangers

The fuel level indicator problems could be caused by a number of components. The easiest thing to check is ground G100 located on the left side of the radiator support in the engine bay. Make sure all connections there are clean and secure. However, this ground is an unlikely suspect due to the fact it is shared by a host of other systems, but again easy to check. Another possibility is the fuel gauge itself, troubleshooting to check its integrity is a subject for another day. In other words I would have to further dig into my manuals. Another possibility is connectors at the tanks themselves, they should be clean, secure and free from corrosion. Finally, the most likely culprit although hard to believe since it involves 2 different parts is the fuel level senders themselves. They exist in a hostile enviroment and never see the light of day, constantly moving up and down in hot and cold. They are the most difficult to access since this involves dropping the tanks or removing the bed.There are also various connectors the system that could be a problem. Check the ground and tank connectors and report back.