hello all !!

I have a e320 1996 v6 3.2 with a 5 speed auto gearbox. The car was running fine but all of a sudden the car has stopped shifting to the 3rd gear on wards or it could be the fourth .... it goes till about 40 miles and then the transmission goes free ...... i have changed the auto transmission oil and filter (drained the torque converter as well) its a 210 body type. please can anyone help....

thanks in advance