2000 Automatic 4.0 TJ 32RH Constant Whistle

[Jimmy's Jeeps]

Hi guys,
new-to-me 2000 TJ 32RH not long after changing the water pump, I start getting a fairly constant whistle sound. Happened at idle maybe 30 seconds after startup, happened while driving pretty constantly, in every gear. While driving between 750rpm and 1600rpm, it would be constant but above 1600rpm the whistle goes away. When I put it into neutral or park and rev it over 1600rpm, it doesn't ever go away. I managed to rule out belt/idler/bearing issues. As well as vacuum issues.
While poking around under the Jeep, I broke a very fragile AT Oil Cooler Line. So, I did a quick repair and the sound didn't come back. Maybe the line was preventing good flow, possibly clogged...Not sure why this repair would have fixed it. But now, 3 days later, its back to the train whistle.
Does anybody have an idea about this?
Thanks

 

[Gilaguy23]

Get a cheapo H/F mechanic stethoscope and try to home in on the culprit. Playing guessing games in a metal box can be deceiving.

 

[Jimmy's Jeeps]

Get a cheapo H/F mechanic stethoscope and try to home in on the culprit. Playing guessing games in a metal box can be deceiving.

Very true. Thanks.

 

[Jimmy's Jeeps]

I may need some special attention from the automatic transmission specialists on the board, somehow my instincts tell me that this one might go deep into the subject. I've owned a ton of vehicles and have never heard this before. It sounds like the whistling of a tea pot, except more expensive.

 

[RHD-06-TJ-4.0]

any update? My 06 just started this teapot whistle soon after a water pump change and reconnecting some vac tubes that were off. The whistle happens after start when the temp gets to about 180/200, it is consistent at idle and while driving. Only time i think it stops is the moment I get on the pedal for a fraction of a second, but only when driving, not at idle.