Glad I still have my haynes manual for the w123. Looked in the trouble shooting section and for difficulty engagning gears it lists

1) clutch not releasing completely
2) loose, damaged, or out of adjustment shift linkages
3) input shaft bearing seized

for slipping out of gear

1) transmission loose on clutch housing
2) shift rods not working freely
3) dirt between transmission case and engine or misalignment of transmission
4) worn or improperly adjusted linkages
5) work synchro units.


I will have to get those bushings on the ends. I need a 6mm diameter rod to put into the alignment holes for the shifter fingers.