Posted over on JK forum too to get other insight as well. Whats your all thoughts on this?
Long story short, my dad was going to trade in his low miles 07 rubi (21,000) for a 12 because it started squealing under load at mid throttle and 3 dealers couldnt find the cause. He offered it cheap to me, lower than the dealer was going to give him. They thought it was like a throw out bearing, or clutch disc problem. Only happened under 1/2 throttle right around 1500-2000rpm, most noticeable in 4th gear or higher. When the noise occurred, if you rapidly depressed the throttle or let off of it the noise would go away instantly. Clutch never slipped or seemed to have any problems.
Fast forward to today after using my Chassis ears which are remote transmitters that you connect clamps to places you think make noise and you can track down the problem. I think a must for every Jeep owner! hahaha. Anyways, I started with the running grear, trans, bell housing, transfer case and nothing..........Kinda sounded like a intake suction noise in a way....So I threw all 6 sensor clamps on the plastic intake and BOOM found my noise in the intake tract. Now what? Why is whistling/squealing all the sudden, small vacuum leak? I did a BG throttle body cleaning and still the noise......Jeep has a AEM intake but my Dad said it starting making the noise somewhat before the install.
Anybody make an all aluminum intake? Maybe throw one of those tornado spirals in the intake tube?
Thanks for the input. My dad is mailing me the stock intake so I can try that. Tensioner or water pump or bearing would squeal all the time you think or change with rpm. This is just a quick whistling kinda sound just at a certain rpm and only at 1/2 throttle as posted above. I tried to make 5 gopro vids from the engine compartment to the drivers seat but it can't pick up the noise for some reason. I'll keep trying it in diff places this weekend to see if it will catch it.
Status? I am having the same issue, 2000 Sahara 4.0L with K&N cold-air intake. The cold air has been installed over 3 years, the "whistling" sound only recently started. I'm pulling my hair out trying to identify it. Mechanic friends say doubtful clutch related. Water pump, fan clutch, and idler pulley 6 months ago new. Have not replaced tensioner pulley.... yet, but I was starting to lean towards that when I came across this thread.