My 04 diesel Ram developed an intermitted squeal recently that has progressively turned into to a constant noise.
I removed the serpentine belt and did some investigating today.
About 4 months ago I noticed my waterpump had a slight leak so with winter coming I decided to replaced the water pump, the pulley on the tensioner, the top idler pulley, the serpentine belt and coolant.
Everything ran and sounded good until recently.
When I pulled the belt today all the pulleys were tight and spun great....alternator, power steering, fan bearing, and AC compressor.
I pulled the tensioner and everything also looked and felt great.
The belt looked great and showed no signs of abnormal wear.
I'm fairly confident there isn't a problem with any of these items.
The water pump turned but had a slight resistance and made a very faint squeking noise, nothing grinding or wobbly, kinda sounded like a tight rubber O ring.
When spun the pump didn't spin continuously, maybe 1/8 turn.
The rest of the pulleys would spin multiple revolutions.
I cleaned up the belt and put everything together and took it for a 5 mile run and everything stayed quiet.
So for the Cunmmins diesel experts how free and how long should the water pump turn when spun?
The truck runs cool and has no cooling issues.
The pumps are easy to replace but I would rather not mess with it if the resistance and lack of spinning is normal.
Thanks.
By far, the easiest water pump replacement I've ever done on any of my vehicles. 
