Probably you had the set screw that holds the plastic handle to the shift lever come out. The button underneath the handle should have a small pin sticking out that indexes with a slot in the lever and a hole in the inner shaft. to put back index the pin in the hole in the inner shaft and put handle back on shifter and find set screw. I have a shifter off an 82 320 that i would let go if you need one mechanically I believe all shifters are the same May have to transfer some electrical parts.