Short Wave Sportfishing wrote:

You might also have a worn holes in the shift rod which is not fully
seating the gears. You might have a worn drive shaft, but that's
unlikely - a possibility though.

Agreed on the wear. Like the possibility of the hole being elongated
from where the cable fits into the shift lever, ether the hole is
elongated, or the cable coupler is worn.

Possible cable stretch? worth thrust on the forward gear, or shifting
fork worn internally, where there's too much lash and gears are barely
catching each other?