Is there any reason to replace the entire wheel bearing housing rather than just replacing the bearings?

Mine are starting to sing and I'd rather replace them now than wait until they get crunchy.

Any idea what size the bearing are? I'd rather buy them ahead of time than after I pull the housing and remove the bearing.

2001 5.9L quad cab 4x4 with 4 wheel ABS.

 

Unit bearings. Generally not rebuildable. So yeah, replace the whole thing. Probably have ABS sensors in them as well.

 

yep, 4WAL will have a tone ring on the hub, and for a 4x4 it's a sealed unit bearing inside the cast carrier.

 

Timkin seem to better than most, imo .
torque to the correct specs., your good .