6.5l serpentine belt issue

[Macmachinist05]

I have a 96' 1097a2 with the 6.5l na engine, no a/c. I am having an issue with the serpitine belt walking off the crank pulley! From everything I have checked so far all the pulleys are in line with each other except for the crank pulley! The crank pulley is 1 full rib closer to the engine than the rest of the pulleys. The belt squeals then walks off one rib to the front of the crank pulley and stops squealing until you raise rpms and then tries to walk up and over the water pump/fan pulley.
I have replaced idler pulley bearing, tried multiple belts, and just replaced the crank pulley with Leroy's diesels solid billet pulley! I have checked and made sure all bolts are tight and not broken or missing in all brackets. It just doesn't make any sense to me why or how the crank pulley could be one rib off, closer to the engine than the rest! Any help on this issue would be appreciated!

 

[87cr250r]

Use a prybar to bump the crankshaft fore and aft. I think it should move around 0.006". I don't have the number memorized.

 

[Macmachinist05]

Use a prybar to bump the crankshaft fore and aft. I think it should move around 0.006". I don't have the number memorized.

I actually did try that! I couldn't feel or see any movement. I did not put a dial gauge on it though!

 

[87cr250r]

The movement is critical. Your engine cannot survive without it. At a minimum you should hear a clunk from the crankshaft if you bump it quickly.

 

[Macmachinist05]

The movement is critical. Your engine cannot survive without it. At a minimum you should hear a clunk from the crankshaft if you bump it quickly.

Rechecked yesterday morning and I do have movement. Couldn't get a clunk but could feel it and see it move slightly! Nothing excessive though. This humvee only has 3,7xx miles on it, and believe it to be true.