Mercedes Benz repair: AUTOMATIC Mercedes C Class Diesel Estate, 2001, mercedes c class, metal shavings

Question
Hello, I bought the car in April and have had a few problems with it.  I'm checking to see whether this is a big problem! Current problem is that the car revs stick instead of changing gear, say from 4 to 3rd or 3rd to 2nd etc. it screams a bit and very often the car seems to sway from side to side.  My mechanic doesn't know what is wrong.  It has had leaks from the gear box which has been repaired and also it has lost power which although repaired happened to my mechanic afterwards but not since  a couple of weeks ago.  I would like to know whether this is repairable and hope you know the reason its happening.  Many thanks for taking time to read this and to maybe solve my problem.  I'm emailing from England.

Answer
do a tranny flush with filter change remember to flush torque convertor also look for any metal shavings in your torque convertor that may be why your car is shifting oddly . check the trans axle also get an alignment for the sway and see what they say.do you have factory rims? I would start with the basics just to save some money .otherwise it may be a pain to diagnose Im pretty sure it is your torque convertor though