Tranny shifting question

Car concerned is a '90 190E (or all 190E's in general). My car shifts harshly from 2-3 and sometimes from 3-4. It's not harsh as in "hard," "really jerky," or noisy. The car shifts properly and the fluid looks healthy and is within "proper level" range.

I know that the shifting can be adjusted via the modulater or something like that. Is this a complicated task and will anything have to be dismantled to adjust it? How much does it usally cost if I were to take it to my mechanic?

I've been driving my car like this for some times now. My main concern right now (after reading similar postings) is that this may not be normal. Will I cause any harm to my tranny if I keep driving like this with harsh ****ing? It really doesn't bother me much, but I really dont want to drive it if it will stress the tranny.

Thinking about it is stressing me, I need a peace of mind. Thanks in advance.