My speedo has always bounced around by 10 or 15 mph, driving back from a 30 mile drive yesterday it started bouncing badly, the cable sounded noisy and eventually the speedo stopped working, I assumed the cable had broken.

On removal the cable was flat and a bit worn through were it clips in the bracket under the car, I put a drill on it, spun it but it wouldn't snag so I connected it back on the speedo spun it slowly with the drill and it held almost still on 30 mph.

So next I removed the blue plastic speedo drive and it was completely stripped, do you think the cable must have snagged to do this? I have re-built the transmission a few weeks ago and was careful to get the steel gear to the front of the land (passenger side cable) and looking through the hole the gear was dead center so don't think this is misaligned or caused the gear to strip.

So the question, is it possible for a snagging cable to strip the plastic gear?

 

Hi Andy,

If you had no issues with the speedo bouncing with a drill connected to cable at the transmission end - it would eliminate the concern of snagging.

Are you sure the correct speedo drive gear is installed? There is an 8 and 5 tooth (if I remember correctly).

Phil

 

A really sloppy tailshaft bushing in the transmission will end up with a stripped speedo gear.

 

The tail house bushing is new, the speedo has been bouncing for as long as I have had the car, only failed completely this weekend. I'm sure the drive and the plastic gears are correct.

As I say the speedo cable has some damage, the inner cable can be seen through a small crack at the transmission end of the cable, I wa wondering if it got hot and snagged/jammed causing the plastic gear to strip.

I will be fitting a new gear and cable and see what happens I suppose.

 

I found that my seized speedo cable had a 2" burn mark where it had come in contact with the exhaust pipe. After I bought a new cable, I cut the old one apart at the place of the burn mark and found that the outer plastic housing had melted into the inner cable, freezing it. Cable was fine other than that 2" section.

My exhaust has a shield attached to it that's supposed to protect the speedo cable from the high heat, but I guess my cable hadn't been shielded in the right spot.