JD670B transmission failure identified.

Thanks for this forum, it's been a support in diagnosing this transmission failure and general knowlege of the machine. I'm hoping to get some advice regarding a JD powershift transmission. Specifically parts for the tow disconnect which RDO equipment Australia (John Deere) no longer supply namely R33227 Pin R116114 Shift Collar. The yoke and shaft are still available ex John Deere U. S.A. R41171 Yoke R42492 Shaft. The transmission identification plate has a number ROT843012453, it's 8 fwd and 4 reverse gears. I was wondering if the parts from these are common in any of the agricultural equipment, tractors? Ive been browsing the net but havent done any good on any supplies elsewhere. Any advice on where to get these parts direct in the U.S.A or elsewhere would be much appreciated. I have family on ground in the U.S.A at the moment so they may be able to assist also. I'm hoping to get a shift collar new as we figure the failure may have been caused by wear in the collar or splines on the gear side and didn't want to risk a worn 2nd hand replacement, although may have no option. I'm no mechanic but have a friend assisting who has some experience with these machines. I'd also be appreciative of any advice in the replacement phase, especially how to get rid of any metal bebrid is in the sump of the transmission from the failure. I've included the sad story of how my transmission problem came about for anyone interested hoping it may help them diagnose a problem if they are unfortunate enough to suffer the same fate. ONCE UPON A TIME Whilst moving in 1st fwd the machine made a grinding noise and went into netural. I engaged the clutch stopped and tried for 1st again but only made noise again, then I got reverse 1st momentarily and shut it down. As is my luck the machine was about as far away from civilisation as is possible beside a river at the bottom of a steep mountain track I had just started to work. I'm no plant mechanic but with the help of a good friend who has experience with these old girls we lifted the motor out, took the tops off the trans covers and found the trans disconnect shoes missing. (We were looking for these after reading a post on this site of a fellow with a similar problem which found the disconnect shoes worn out). After locating and purchasing a second hand pair of shoes we set to pulling the disconnect apart (with the help of a service manual) only to find the shift collar smashed with most of it contained in its place but two small pieces located in the oil in the bottom of the sump. We couldn't find any sign of the disconnect shoes which are brass. There was no damage to the gear to which the collar connects but the disconnect shaft and yoke were bent. Thanks for any advice. All t the best.