Please Help! clutch problem

I am new to threading and to the Honda Passport! We got it really cheap with some transmission problems. All the gears inside were stripped and the clutch was bad. Picked up a used Isuzu Rodeo transmission and a new clutch set. We have been through 3 clutch sets because the retainer ring will not stay with the pressure plate. Now we cant get the bearing to lock into the pressure plate. :disappoin Any ideas?? or anyone have the same problems in the past? Thanks!