C250 diesel auto gearbox problem

[HMR]

Have recently aquired a C250D. We are very pleased with the car except for a (sometimes very) sluggish gear change from 2nd to 3rd when cold. The car has only done 70000 miles. The concern is that the problem will deteriorate. Any information/ suggestions gratefully received.

 

[MW]

Cheepest option is to change the gearbox oil and filter. Europarts can supply the filter and rubber sump gasket for about £10. Oil is about £10. What colour is the oil? Anything less than nice and red is an indication its time for a change. On a 'new' secondhand car, if you are not sure of the history, I would change it again with the filter in a years time.