I have a 1955 D6 8U that seems to have a lot of free play in the forward / reverse lever. I have a spare machine with transmission that has a very clear detent feel when moving between its three positions, however the operational machine does not. All the way against the floor plates in both directions, anything less and its just in neutral.

I have not been able to find much about adjustment or details drawings in the service manual or parts catalog. Anyone with experience that can help me understand the likely cause and possible route to improvement ?

Thanks
James

Given your description of going from floor to floor and if your lucky it could be just a loose bolt on the forward / reverse lever itself and a worn out key. If your unlucky it could be a loose bolt on the lever inside the transmission or less likely a problem within the detent block.

if it is like phil suggests a worn keyway you might be able to fix it with a little devcon epoxy. ive done that my self to patch a key way that had wallowed out a bit on a waste extractor fan.