Was there any oil in the Transmission?
I have seen where guys think the TRX450R/ER is like most other quads and don't realize that the Transmission and the Engine oil are separated and run their transmissions dry with out realizing it. Also remember too the Transmission is supposed to use a Wet Clutch Oil. Or a Gear oil like 80-95 weight
If you decide to do your clutch plates I recommend replacing the Inner and Outer clutch baskets because they become grooved.
Build Break Rebuild Better