Speedometer issues

[randomq]

Howdy,
I've got an 89 F250. It started out as a 2wd, C6 truck, but I've swapped in a ZF5/1356 and dana 60 from a 90 F350. When I did the swap, I replaced the speedometer cable, because the old one was very obviously broken.

The speedometer has been reading a little slow since the swap, but it worked smoothly. Now, it's reading REALLY slow and bouncing all over the place. The odometer would appear to be working correctly. How do I fix this?

I've been using my GPS as a speedometer, but I really like having a accurate, working speedometer.

 

[franklin2]

Pull the plastic gear out of the transfer case and inspect it. Also while you have the cable out of the transfer case, twirl it with your fingers and make sure it's smooth.

 

[randomq]

I don't know why I forgot to respond to this, my speedo still isn't working and I don't know why. I pulled the cable end out, spinning it with my fingers while watching the speedo, it looked to be working fine. The gear on the end looked fine and the gear in the transfer case looked fine and seemed to be firmly attached to the shaft (not slipping).

Since my truck started out Auto/2wd and is now 5-speed/4wd, there is a chance that the folks who did the work for me put the gear from the automatic on, instead of the one from the manual. Could this be my problem?

This thing is really aggravating me, because I'm a stickler for obeying speed limits. Also, odometer is NOT working and the speedometer is working for maybe ten seconds of a thirty minute drive, randomly.

 

[flareside_thun]

It's got to be the gears. it's either one or the other. Make sure your gears are coming into full contact with each other also....and that the speedometer cable is correctly fastened into the tailshaft housing.