Hi there Chris.

You can check your diff lock by going for a short spin. Find a parking
lot or something like that. Stop the vehicle and pull out the diff lock
switch on the dash. It takes a few seconds to engage, well mine does.
Start to drive slowly and turn the wheels, the front wheels should start
to jump a bit, resisting the turning. Don't do this for too long. It is
not really designed to be used on pavement, but rather mud, gravel, snow
etc.
A possibility about the binding in reverse, could be one of your front
outer CV's when turning sharply. Mine used to bind (difflock off)turning
sharply when moving forward. I had an outer CV that was worn, passenger
side.
About the play on the front right, my front axle also has more play than
the other side, but all mechanics say it is fine. I don't know if we are
talking about the same thing here. Good luck.

R.Feuerriegel
88 syncro in Victoria

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