Speedometer: Speed yeas, mileage every 5th

[olut]

Hi A-Friends,

I searched for this problem without success, I just found a reverse one.

I do have pretty accurate speed but mileage counts about 1:5 less, same does day counter.

My speedometer is original with 44.500 mi. This problem is not dramatic except when participating at classic car rallies. Can anyone recommend me an experienced repair expert, whom I can ship over the unit next winter for a fix?

Many thanks in advance, Albert