Speedo drive gear not right

[Bullifamilie]

Put locking front diff in my syncro a while back, all going well, I just need to sort out the speedo.

I thought I had checked the speedo drive before installation but obviously not very well. Observing by spinning one wheel I get the following;

Initially the speedo drive won’t turn. If I encourage it a bit it will turn a full revolution in either clockwise or anticlockwise direction then it stops again until I encourage it again.
I can’t visualise the gear mechanism inside. Is the drive stopping because it’s working it’s way out i.e. disengaging or is the drive gear likely to be broken.

Secondly, assuming I buy a new drive gear can you match it to your wheel size?

[Aidan]

the speedo drive has a nylon cog on the inside so that when it seizes it strips the nylon cog which doesn't create any damaging debris as the speedo drive is adjacent to the pinion bearing, sounds like yours is partially stripped and rotates until it reaches the flat spot.
If you remove the speedo drive the nylon cog is colour coded, count the number of teeth and report that and the colour of the nylon
Some are still available new, I have a few used and one new one in stock; also on the front diff the speedo code may be stamped under the code, eg ADM D, I can work out from that what you should have in there, they were originally determined by tyre size and final drive ratio

[Bullifamilie]

thanks Aiden,

seem to remember it was red. I'll see what numbers I can find and send you an e-mail.

I do have a spare from the diff I removed, although a new one would be best if it's still available.

[Aidan]

Red 21 available new only