I have been having a noise that I cannot tell where is coming from. It happens at full throttle shortly before shift and most noticable @ 1st to 2nd shift. It sounds like either a belt slipping (doubtful), a bearing not having enough oil at the time (5200+ RPM), or maybe a bearing or somthing in the tranny. It goes away immediately after shift and I swear I hear a little belt slip right before and during the shift. It could be a combination of things, I just want to make sure I don't hurt anything. I have been letting off briefly to let the truck shift without a load to try to limit this. Any ideas?

 

it could be your alternator. My crown vic does the same thing under full throttle but that's because it shifts really hard.

another thing to look at is the belt tensioner my buddy's chevy was doing that.

 

Smoke i have heard of this a few times, and all times it ended up being a damn pulley of some sort. all the same symptoms as you. also it ended up being the pulleys were just getting enough vibration at a high RPM that it would shake the belt enough to make it squeal. Just a thought, i would loosen the belt and feel your pulleys, and make sure there is not one that has some play in it.

 

It does sound like pulley's. Hey smoke, this is a perfect time to upgrade and purchase some performance pulley's.

 

I have heard concerns with the performance pullys and the weak alternator that chevy is using in these trucks. I can tell now that the lights dim a little when at idle compared to moving. Is this really an issue or no big deal? SC_CHEVY didn't you say you were getting some new pullys?

 

Also where do you get these pulleys? I am having some trouble finding them for my specific year.