If the fan hub bearing in your '89-'26 Dodge Cummins trucks is making noise or the base for the cooling fan is loose and wobbling, don't wait to replace it. If it fails a lot of expensive damage can be done to the radiator fan, sensor and possibly the radiator.
Replacing the bearing is not very difficult, but you will need access to a press or have someone press the bearing into the fan hub for proper installation.