Jethro,
Do a web search with "1954 3100 rear axle seal". You will find a host of current vendors selling just the seal. The prices are for the most part pretty close to each other. Your choice on which vendor to choose.
bigedpa,
Tim's links all worked for me this morning. I did a quick check of a couple vendor sites (Not Mine) -
The Filling Station
https://store.fillingstation.com/dept/Transmission/cat/Differential.html Chev's of the 40's https://www.chevsofthe40s.com/dept/Rear+Axle/cat/Ring+%26+Pinion.html (unknown why this link doesn't display correctly? cut and paste works)
Both show different kits for 1940-50 and 1951-54. Hope the info is helpful!
