My speedometer has gone crazy

[Rocko]

Finally got my tranny rebuilt in my Capri and drove it for the first time the other day

My speedometer cable jumps rapidly back and forth; My dad says it was working when he drove it before I started working on it. What would 'cause that, it's driving me nuts?


I'm not sure what the cause is. Once we got it home, I gutted the inside (paint, etc...) and then took it to the tranny shop so I never really tested/noticed it

Thanks
Rocko

[Matt82GT]

could be the cable or the gear. im not sure which one though. anyone....?

[Cappn Tripps]

alot of times it's the cable binding because it dries out.. drive it for awhile and it may go away..

or the gear is broke... pull the cable out of the tranny and check it too..

[Rocko]

or the gear is broke... pull the cable out of the tranny and check it too..

When you say Gear, is that something I can fix easily? Where is that located (the Gear)?

Rocko

[FoxChassis]

There are two gears: a drive gear (inside the transmission, on the output shaft) and a driven gear (on the transmission end of the speedometer cable).

The drive gear is not easy to replace (especially in an auto). The driven gear IS easy to replace....

Remove the speedometer cable from the transmission. Remove the clip holding the driven gear to the cable. Remove the driven gear from the cable. Installation is the reverse of removal.

[Rocko]

Thanks alot for the infomation. I'm going to take a look at it tommorow.
I hope the chance of it being the drive gear is slim since it was just rebuilt, but you never know :... I have a warrenty on it so I may just take it in if all else fails.


Thanks so much, I'll keep ya'll posted.
Rocko

[Bananas]

Having been a speedometer mechanic and rebuilder in my past, the usual cause for the problem as you discribe it would be that the cable itself had begun to fray and would temporally hang up inside of the casing, causing it to stop spinning. The drive gear was still turning the cable down stream of the hang-up, in essence loading the cable to the point where it would release and spin off all of the stored up energy. When that energy is released it briefly spins very fast until it unloads. When it is in this brief fast spin mode it causes the needle on the speedo to respond.

Slide the cable out of the casing from the tranny side. If the cable is frayed, it is best to replace cable and casing together. Hope that this helps.

Bananas!

[rbohm]

banana's is right, also sometimes if you kink the cable sheath, or force it to bend too tightly, you will get binding as well causeing the exact same problem. i know my falcon has that problem.