pilot bearing keeps getting chewed up

my brother has an 89 s-10 blazer, he replaced the trans 2 yrs ago, he noticed then that pilot bearing was chewed up. he is in the process of replacing the clutch now and the pilot bearing that he put in two years ago is completly chewed up agian. i want to know what causes the pilot bearing to get chewed up? thanks.

To some extent this can be normal, more so if he hotrods/abuses it. Good to get this replaced as the extra movement of the input shaft in the transmission will destroy the roller bearings and surface on the main shaft inside the trans. The bushing is an oil impregnated bronze material but doesn' t hurt to put some grease on it.