Rear Bearing Replacement on Tri-z

[Just-Tri-It]

Bought a tri-z for a roller, plastics been repainted but good motor and trans. But I believe the rear bearings are going out. I believe its the carrier bearings. I have a manual but wanted to get as much other info on it before starting. Any special type bearings recommended or just oem. Any tips or tricks to making it easier? Are the bearings the only thing to replace while it's apart?
It makes a a little screeching sound or metal to metal type sound, but I knew this from the beginning.
Thanks for the input.
sheeptender