I remember that you helped me on the way to diagnosing this problem.
Parts were going to cost about $12,000 (JD knows how to charge here) and some parts were difficult to get.
Labor was also very expensive then (middle of the mining boom and most good mechanics had headed off to cash in at the mines). Labor costs have eased off now but are still close to $100 per hour. The big labor cost was getting the cab off and getting at transmission.
Traded the 3350 on a new 6330. It is the utility tractor on 4,500 acre grain farms. Main farm work is done by 8000 series (not mine) JDs in no till system.