This may sound like a stupid question but I'll ask anyway:

On my newly purchased '76 124 Spider I noticed that the gearshift knob turned and I thought it was worn theard on the shifter knob.

After looking a little closer, I found that the know was tight but the shift level was loose. I assume that it shouldn't turn?

Thanks.

Mine has turned since the day I bought it new in 72. Everyone that I have had or driven does that.

My recently purchased 76 did the same thing. I removed the shift lever by taking the nut off of the bottom of it from under the car and found where the problem lies. There is a "Knuckle" formed around the shift lever right where the finger sticks out on the side that moves the housing back and forth to change the gears in the transmition. This "knuckle" was broken allowing too much slop around the finger, which would disengage from the housing and spin freely. I ordered a replacement shift lever, installed it and it works just like brand new! As an FYI, the other 6 or 7 parts that were part of the shift lever were all fine, just the lever itself needed to be replaced.

Good luck!