Classic/Antique Car Repair: 67 Chevy 3 speed, mr gasket, speed tranny

Question
HI,I have a '67 Chevy truck with a 3 speed tranny.In March I switched to a Mr.Gasket floor shifter.All was good for awhile,then the gears started getting jammed coming out of reverse every now and then,and at times will get stuck in first.Gotta crawl underneath and work the front lever free and center them up.2nd and 3rd gear are fine.I checked the fluid,was a bit low,so I added some 80-90gear oil.Helped for a few days,then started doing it again.Now it happens a couple times a day.Any thoughts?

Answer
The dogears that go on the transmission are not as harden a metal as the originals and usually get wallered out at the slot that fits on the shifter rod coming out of the tranny. Check and see if when you move the leakage the dogear doesn't move a little before it starts to move the rod. I imagine that is your problem