Don't take this the wrong way Doug, but your post surprisingly sounds like you're trying to make an excuse for wrong information. I get sick of all the misinformation that gets spread around, and I like to educate people with the correct info.

To answer your questions, it doesn't happen the same on all trucks. Some trucks have the noise with a pulley, some don't. Some trucks even make this noise STOCK. Some trucks do it at an idle in neutral, some only in drive when the rpms drop. Changing the by pass setting puts a different load on the rotors, so naturally that will change the noise too, although your by pass should be open at idle anyway.

The reason for all the variances in symptoms is from the tolerance differances in the blower from unit to unit.

 

Gee, it's nice to use a tuner that know's and understands our trucks. Time to spend more money

 

Sal is this condition what ever we decide to call it, can it be made worse or louder with the cold air ? Mine seems louder when the temp is below say 40 or so?

 

i have the same problem to, sounds like marbles tumbleing. happend after i got the 2# pulley. i knid of understand what it is. all i want to know though is that its not hurting my engine. its not, right?

thanks
joe