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LB7 eating serpentine belts

Landon730

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When I got my truck the front rib was completely gone off the entire belt so I bought a new one and put it on... 1500 miles later I noticed the front rip is starting to fray and get eaten again. Got to looking today and the front rib jumps up onto the front of the harmonic balancer. Tried reinstalling it and as soon as you start it, it happens again. Belt is on all the accessories correctly except I noticed its running further forward than the polished spot on water pump. Tried scooting it back and aligning harmonic balancer for it to do the same thing again. Could it be the PS pump? Can barely turn the tires if the truck isn't moving and I figured after 400,000 miles its just wore out... unless the belt is holding it wrong and the pulley is out of alignment. Just hoping someone has had a similar problem who can help
 

NVW

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Turn all the pulleys with the belt removed to see if any pulley is seized up or stiff. Use a straight edge to see if the pulleys are aligned.
 

Will L.

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The crank pin wears and lets the balancer wobbleor move. It can shear, loose balancer timing and break the crankshaft. Search “duramax lb7 crank pin kit” on google, bing, etc and you’ll see it.
Simply inspect for freeplay on balancer, and if you haven’t repinned yours yet- schedule some time for it.

The bad balancer ruining crankshaft and block isn’t just a 6.5 thing. Many diesels have issues of it.
 

THEFERMANATOR

FRANKENBURBAN
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I've yet to see a balancer spin on a stock truck, just what I've seen. Check your power steering pump pulley and make certain the front of the pulley is flush with the end of the pump shaft. This can cause your issue(did on mine).
 

Landon730

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I've yet to see a balancer spin on a stock truck, just what I've seen. Check your power steering pump pulley and make certain the front of the pulley is flush with the end of the pump shaft. This can cause your issue(did on mine).
Ok I'll try to if I get time tomorrow, been super busy between work on other more important problems with the truck lol
 
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