# Underdrive pully squeeling?



## lukekeith (Oct 27, 2006)

I just had an underdrive pully and GMM rip shifter installed last week, and the last few days my car has been making a pretty annoying squeely noise that seems to be coming from the engine whenever I push the gas, even in neutral if I rev the engine it makes the noise. Is this normal? Should I be worried? I assume it was caused by the underdrive pully since it didn't make the noise before it was installed.

Any ideas??? Anything you have to offer would be greatly appreciated.


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## 05GTO (Oct 6, 2004)

Go with a shorter belt, I believe my new belt came from NAPA for around 30 or 40 bucks.


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## mtjoy (May 3, 2007)

^^What he said. Did you change your serpentine belt and the a/c belt? I've heard of others that have had to go to a smaller a/c belt to stop the squealing.


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## lukekeith (Oct 27, 2006)

And the A/C belt? Hmm, might have to check that one out... Does anybody know if having a belt a half inch too long might affect the performance gained from the underdrive pully? As far as I can tell so far, outside the squeeling/slipping it doesn't seem to be bad, I just wonder if I'm not getting the full performance out of it because the belt is a hair too long.


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## ls2weber (Apr 21, 2007)

The belt should not change your performance but if it's slipping because it's to long you could be opening the door for all kinds of problems. You got to think of all the things that belt drives I would go with the smaller belt plus you don't want to be that one case that the belt comes off.


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## mtjoy (May 3, 2007)

A 1/2 inch difference would definitely make a difference. I believe with the SLP pulley they recommend a 405K4, but some guys are going with a 400K4 which is smaller yet.


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## Guest (May 6, 2007)

*under drive pully*

Who did you get your pulley from.. when I ordered mine, it came with 2 extra belts,,


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## Guest (May 6, 2007)

*pulley*



mtjoy said:


> A 1/2 inch difference would definitely make a difference. I believe with the SLP pulley they recommend a 405K4, but some guys are going with a 400K4 which is smaller yet.


The belts that SLP send with their under drive pulley stretch very quickly, my 1st one was useless after 200 miles.. I tossed them both in the trash and got 2 more from another speed shop,, No problems with the other one


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