I found this posted on a Tool Tech Web Board - hope it helps you out.
Thorsen tools used to be part of Olympia Group which went bankrupt in 2006 and was purchased by a Chinese firm. Thorsen was sold to Woods and moved to Carmel, IN.

Iwould send a letter directly to the Office of the President at the address below and mention the problem you are having.

Note that the fellow below had to wait 7 weeks for a replacement.

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Posted by Steve (IA)

I ask this board a while ago for help finding supplier of Thorsen tools as I had some sockets that were worn or broken and wanted to try their guarenteed for life claim. I got their new address (below) and sent in 4 1/2" drive sockets.
7 weeks later the UPS man knocks on the door with 4 brand new in the package sockets. The look good, bright and shiny. Package says imported from Taiwan and Lifetime Warranty. Hope these last as long as the 1st set did. I remember my dad using these tools in the early 60's, but don't know when they were new.

For replacement:
Woods Industries
510 3rd Ave.
Carmel, Indiana 46032
1 800 428 6168 Steve"