turbo flutter?

[reddoc99]

I am currently running an all stock 99 f350 2wd srw with 140,000 miles. I am the only single owner of this truck with a manufacture date of 1/99. For the past 4-5 months I have noticed a siren-type sound from the turbo at midrange rpms (1400-2000) during normal driving. There are 3 inch boots attaching to the manifold covers, therefore I think this is considered a 99.5 garrett turbo. No boost gauge in truck. No noteable performance loss is noted either. I have read the extensive posts on turbo surge, stall, flutter, etc. I feel this is turbo flutter or an early weak surge. I removed the intake to look at the compressor wheel and it spins freely and has NO play in/out or side/side. The fins do not show any wear, cupping, or points on the ends. The compressor housing shows no grooves. My question is... how can I still have flutter or surge if there is no "play" or is this just the wheel slowing intermittently creating the siren-like noise. The turbo shows no noteable signs of failure (smoke, loss of power etc.) What to do now????

I have casually read posts from this site for 7 years now and truly feel that I stay informed. Thanks for any and all replies.

[Pocket]

It could also be the serpentine belt, or tensioner pully. My parent's 03 made funny noises like that at higher RPM's that sounded like the turbo was on its last legs. Swapped out the belt and tensioner pully and the noise is gone.

[INFRNL]

flutter or surge doesnt mean something is worn in the turbo. we use PSD's at work and some of the newer trucks even have turbo flutter/ surge. but it doesnt sound like a siren either its more like a whooshing. sound to me that it may be something else as the above poster mentioned

[fatyesno]

I have significant turbo flutter, but it only occurs at high RPMs when the boost hits over 25 lbs of boost due to the TS chip. It sounds like a whoosing sound, and mine flutters due to the wastegate trying to dump the excessive boost. I do not think yours sounds like a turbo flutter.