If the only seal you're trying to replace is the one around the shifter shaft, just drill a small hole in the metal ring and use a sheet metal screw to give you a place to pry on. The seal will come out more or less intact that way so you can examine it for part numbers. I just measure the diameter of the hole in the housing and the diameter of the shaft, and buy an appropriate-sized seal from a bearing supply business. All of those places will have a progressive size chart for lip seals. Just get a seal with the right inside and outside diameters, and the right thickness.
The seals around the rotating shaft(s) can be replaced the same way- - - - -no need to disassemble anything. If any bearings or bushings are sloppy loose, a seal change will be a very temporary fix.
Jerry
