With a little bit of effort I was able to get the Fleetstar running. The RD450 seems to run pretty good although the rear main seal leaks like a sieve. But with the truck running I was able to start evaluating what worked and what didn't on the Gar Wood crane. The boom up and down seemed to work normally, while the hook up/down went up, but not down consistently. The boom slew left/right seemed to try to work, but the boom would barely move.
Each of the three operating levers on the crane actuates a selector box, with the output going to the winches via a chain. There are three selector boxes, one each for slew left/right, hook up/down, and boom up/down. The input to these is via chains from the PTO shaft.
These photos show the slew selector box installed, and the input side of the three selector boxes from the rear.
The three selector boxes for the boom up/down, hook up/down, and the slew are basically a small transmission with a slider and two clutches, allowing the pto input to have a neutral, forward, and reverse. I did some trouble shooting on the slew selector box by disconnecting the control lever and operating the control at the box. This bypassed any play in the linkage. I found that to get any movement I had to have the control shaft at it's stop limit. It would usually slew to the right, with effort, but the left would barely move unless I slammed the control, and even then the movement was very intermittent. This told me that I had an actuation problem but it seemed the gearing was working as it should. When I took the cover off the selector box the problem was obvious. The slider engages two small arms on each of the two clutches, and those arms are extremely worn. It looks like I will have to complete disassemble the box the get the clutches out and get the arms repaired. The top of the box also had a pretty good sized crack but that is not contributing to the problem I am having. I'll get that welded up while the cover is off.
While removing the selector box from the crane base I noticed a connecting rod from an old engine jammed between the selector box and the crane tower. I wasn't too surprised since the truck had been in a junk yard for years. Then I realized it was being used as a shim to adjust the pto chain tension on the box ! I guess you just use whatever is handy.
Notice the connecting rod "shim" in upper left of 2nd image. 3rd & 4th photos show worn actuating arm. 5th is crack in housing.