With the long nose shifter does the car have to be moving or can you preload the shift sitting still? The car I am working on has a left hand shift lever, I have broke the handle off twice. From the broken welds at the lever to cross shaft, it was ready to cut loose the first time anyway.
I have the preload on the housing set to shift with a 8 to 10 inch wrench. Except for the rollers on the yoke everything else looks to be good. New housing and roller in the plunger.
The link between the shifting lever and shift housing is home made thin wall conduit and is fairly contorted to go around the battery box. The guide is in place.
You should never try to force a shift in a RUCKSTELL when you are sitting still. The slide gear has to line up with the sun gear and that rarely happens when you are sitting still. If you are sitting still you can try a VERY GENTILE SHIFT, but don't try to force it or you can brake the shifter housing.
Some where, some how I got the idea that you could pre-load the shift.
I agree with Dave in that you must be moving forward when shifting a Ruckstell.
I had a Ruckstell rod from the shift lever to the shift housing made of thin wall conduit once also, but it didn't hold up. I now have the much stronger version available from the vendors, and it's quite strong and works fine.