Hello idahank,
I have no knowledge of a transmission bolted to a 22R that would be manually operated.
BUT... if I were looking for one, I'd call Marlin at Marlin Crawler.
I'd call - Todd at HMC Offroad in Mesa Arizona - 480.454.9397
I'd call - Trail Transmissions in Apache Junction, AZ - 480.986.7367
I'd call - Advance Adapters - Paso Robles, CA - 800.350.2223
Please let us know what you find.
Gnarls.