I have a 83 C20 14 volt 410 real axle. I had the rear axle seals (aka wheel seals) replaced at a differential shop and they used the one piece style. The seals leaked and ruined my rear brake shoes. I had them install the newer style two piece seals and have had no leaks since then (about 20 years ago.) To get the 2 piece seals you need to contact a Chevy dealer and ask them to search their system for a later model 2 piece seal. It may be listed as an option for your model year, but I don't know when GM switched over to the 2 piece seal. Some dealer parts departments don't like doing a lot of research for older vehicles and parts for older vehicles are not online, so they may have to search old paper parts listings and most dealers have gotten rid of paper parts listings. I would not use anything but a 2 piece seal. Good luck.
