Recently got a ap1 s2k. Their seems to be a slight wine like a super charger while driving in gear around 3k rpm. I've done a alot a reading and searching..

Does any one else have a slight wine like a super charger once hit 3k rpm? Seems like it only appear when I'm near 3k rmp. Possible a bad rear diff or trans?

Sound go away or can't hear it much after going any higher then 4k rpm. It only happens when I'm in gear and is accelerating near or at 3k rpm. If im not in gear and

rolling in neutral I don't hear anything. Planing to change out the fluid but have a car in the garage with issue and is using up my jack & jack stand..

Was wondering if it's normal or an issue..