S-10 t-case swap ?'s

ok...before you guys start yellin about doing a search, I have already been there, done that with very little luck. ok, I have a 96 ZR2 s-10 with a 4L60E and 233 t-case. are there any 4-1 kits available for this t-case and if so who makes it? I was thinkin that my t-case is the same as the 231, except that it is push button instead of lever activated...could be wrong, if so let me know! Are there any other t-cases availble that I could swap in to get that lower gear and be a bit stronger? Thanks in advance

Brian