Or you could hook the transmission line up to a mightyvac and as you pickup speed ( the shift points on the speedo) pump the mightyvac and it should do a smooth shift around 9 to 13 " of vac. My 240d has and unusual shifting pattern , until I did this and it shifts quite smooth. It's matching the two together is where the determination comes in.

82' 240d Suzy
82' 300dt Lizzy