shifting problems

Just found this on my 340 four speed combo yesterday. I was having some hard shifting when the engine was running. Seemed to be mostly first. The tranny was rebuilt months back with nearly zero miles on the 833. I had a friend sit in the car and push the clutch multiple times while I watched the bell housing. There was a slight movement of the bell housing away from the engine as he pushed the clutch pedal towards the floor. I tried tightening the bolts on the bell to engine interface adjacent the Z bar. The bolt was tight. I removed the bolt from the bell housing. What a PIA getting my hand and wrench down by the firewall. Bolt was removed, threads on the bolt looked like new, no galling or crap on the threads. Choice time. Add another washer to the bolt or grind a thread off of the bolt. I took the bolt to the work bench, screwed a nut on the bolt. Fired up the bench grinder, took off one of the threads. Touched up the end of the bolt with a file. Removed the nut off of the bolt. Reinstalled the bolt into the bell housing. Tightened the bolt. No more movement of the bell from the engine. I guess the bolt was bottoming out in the blind hole of the engine block. Another mystery solved. Now to address those pesky rubber front brake lines........