Orion case #309, was in a 40 bought by friend Ben Delp two years ago. Couldn't shift it out of high range. Pulled it out and replaced (temporarily) with a spare from my garage. Upon disassembly it was found that the low speed gear on the out put shaft was welded by friction to the output shaft, had a helluva time getting it apart. Obviously it was assembled with little or no (even negative) clearance when the thrust washer was installed. Couldn't tell if the washer was stepped or flat the way it was galled up.
Ben bought a new output shaft, low speed gear and a bearing and seal kit for the repair. Found that the replacement gear wouldn't work, apparently his Orion was an earlier 3:1 ratio. Had to buy a new idler gear to match up with the only available low speed gear, now it's a 4:1 box, certainly an improvement for wheeling. Went together perfectly, I used flat thrust washers to set the clearances on the high and low speed gears both were in the .011" area. Just waiting for an opportunity to get it installed in Ben's 40 to see how everything worked out.
If for any reason someone has a need for an idler gear with teeth counts of 25 and 46 let me know; it's like new.