Replaced the three easiest pullys but grinding noise still there how to find out what pully is bad

Sounds like you have an idler pully trying to seize up and the belt is smoking because of it sliding on the pully. In that case you would need to take the belt off and check all idler pullys and the belt tensioner and replace the one that is hard to turn or feels rough when turning by hand. Ihope this helps you in the situation. Jesus loves you, John 3:16-17 (KJV)

bad bearing in pulleys need to be replaced

Please - for safety sake take your vehicle to a shop.

easy way to isolate the problem is to remove the engine belt and spinn each pully, the only one you cant spin is the crank pully, if you feel/hear any wierd noises then you need to replace it

if you have climate control the a/c comp. comes on
intermitently if the clutch is going bad thats a suspect also the idler pully bearing could be tired
or the ps pump could be binding.
one way to narrow the field is the next you shut it off
after driving a short time see if any of the is noticably
hotter than the others thats a place to start.
hope this helps good luck

you will need to remove the belt and spin each pulley to find the bad one.

you need to go to a service station to have checked out could be any number of things on front of engine drive system

pullys have bearings and the bearings will go bad. what you need to figure out is what pully is makeing the noise and replace said pully. another problem you might have is the power steering pump. check the fluid level to make sure it's not low or dry. when a power steering pump goes bad it makes some noise. another possibale problem is if the car has a/c. the a/c compressor has an internal clutch that will make a grinding noise when it goes bad. To test this start the car turn you a/c on or your defrosters on and listen for the noise in the lower front area of the engine compartment (usually the lowest front pully). shut off the car and look for metal shavings on the pully. for this you should take the car to someone to evacuate the system so you don't release refridgerant into the atmosphere (it is also very flamable) and will need to be oiled with 134a oil and recharged after the repair. hope this helps.

The pulley on the water pump is separate from the pump on both the 6 and V-8 engines (you didn't specify which engine was in your truck).
If the pulley is wobbling around and grinding, the bearings have failed on the pump. The fact that it has not leaked is not unheard of. REPLACE THE PUMP! Continued operation will cause the impeller (the side of the pump which moves the water) to chew up the housing. Not to mention leaving you stranded.

how many km or miles on it if over 140 000km then should be needing an alternator the brushes should be down to springs .and the bearing could of been out of the idler pulley back side