*Note: this pressure tank can now perform a cooling system pressure leak test as well . Kent's 2-in-1 invention. See below to purchase the pressure testing cap.
These drawings should help if you have to remove your transmission and work on the linkages. Sometimes it can be a little confusing when going to reinstall the rods. I know from experience! :-)
Transmission linkage - 1974-1981 240D. Arrow at top shows locking pin installed prior to adjustment.