i just bought a 240d and the trans is actin up

[gezpacho]

i have just bouht an '82 240d and the transmission won't shift unless i floor it. then it shifts quite hard. this is mainly on second gear and less in the progressing gear shifts. when it downshifts there is nothing wrong. the man i bought it from said that i needed a new vaccum modulator. is there anything else that might be causing this problem and is it fairly common for a car this age or does it indicate someworse problems? the shift points are as follows 1st 30mph, 2nd 40mph, 3rd 55mph, od high 60's. any help is appreciated as i am completely new to both diesels and mercedes.

thanks everyone
juan.