If it's the bushing you are looking for,Jegs has them. They carry Energy Suspension Polyurethene bushing part number 335-3.1111G. (bitch to put in).
Thier phone number is 1-800-345-4545.
If its the bracket that is on the transmission crossmember, good luck. you may find one from someone that changed to a 700 or 400 and has the original crossmember laying around.
If you need the steel part, and know someone with a machine shop let me know as I have the original prints for that part and maybe we can have a few made. Good luck, Turbota.