Hi,
I have a 1982 300D with only 80,000 miles on it. The transmission shifts nicely through all gears except from 3rd to 4th--here it sort of revs (flares?) before it drops into gear. Someone told me it could be a vacuum modulator problem but my mechanic says that would only cause clunky shifting, not the other way round.

Please, please ya'll tell me it doesn't mean I am going to have to replace/rebuild the transmission because I really can't afford it!

Also, this problem seems to be worse when the car is cold.

Is there any kind of band-aid fix? Any replies will be appreciated.

Thank you ever so kindly.