Just started tear down and rebuild. Kit from standard gear only one now available for this transmission. Most rebuilders (including Marlin Crawler) have discontinued these rebuilds due to lack of availability of a necessary countershaft bearing.
I located a factory original on eBay and snagged it. So on with the rebuild.

The transmission was a spare I had in the shop for years. It worked fine, but figured better to do a complete rebuild now rather than wait for future problems.

The kit (less bearing) sells for about $350.00. The parts you see next to the box are all that come in the kit. Very expensive little parts.