Have a HD Marlin rebuild L52 in an 83 SR5. Do not have too many miles on it even though I put it in in 2011 as it is my trash hauling truck. Have a recent issue with it not allowing me to use 1st, 2nd, 4th or Reverse. Working with Marlin, suggested possible issue with shift seats and socket. While I installed new seat and socket at the time of the trany install, after discussion, started truck, pushed shifter down and pushed around which didn't move much but it got it to shift in all gears after working it for a bit with that in mind. I have ordered Marlin's HD shift seat and sockets and will pull the shifter, inspect and install the newer parts. Will update as I go along.
If you have an L52 you need to see Turbo's rebuild, it is awesome. Here is the link TURBO's L52
http://board.marlincrawler.com/index.php?topic=85167.0
