Whistling / high pitched consistent chirping from transmission pan?

[Flcnj94]

2002 4.0 184k miles auto

When in drive or reverse, there is a noticeable high pitched whistling/bird chirping-ish sound coming from the trans pan of my TJ. It seems to begin once warmed up and will occur while idling, but goes away when moving. It stops when placed in park or neutral as of lately (but it used to do it in park sometimes as well). The trans oil looks clean but does have some transparent bubbling (not creamy/milky). When using a stethoscope the noise is definitely from the trans pan and sounds almost like high pitched whirring/whistling with movement. You can hear it when standing beside the jeep it’s pretty loud. I linked two uploaded videos, one of them is just the sound from underneath by the trans pan, and the other is from idling in my garage and changing between drive, neutral, park:

https://files.fm/u/ucs3sk99t8

Any ideas for what this could be? It’s been happening consistently for a while and it doesn’t seem to have effected performance but I’m not sure what to do. Fluid flush and see or have it inspected or?

 

[TJ Jim]

@Irun might have a suggestion. I’m thinking he rebuilds them?

 

[hear]

That sounds exactly like what the low/reverse drum sounds like if the overrun clutch isn't lubricated. First one I ever reassembled, I didn't lube that roller clutch initially, and it made a high pitched squeak like that when I turned the drum by hand. Not saying that's what your issue is, but I've heard a simiilar sound before. If that noise just started, I'm wondering if that roller clutch isn't getting ready to snuff it.


Does it go away when you put it in reverse? In reverse, the L/R band holds the drum so it won't spin inside that roller clutch.

 

[Flcnj94]

That sounds exactly like what the low/reverse drum sounds like if the overrun clutch isn't lubricated. First one I ever reassembled, I didn't lube that roller clutch initially, and it made a high pitched squeak like that when I turned the drum by hand. Not saying that's what your issue is, but I've heard a simiilar sound before. If that noise just started, I'm wondering if that roller clutch isn't getting ready to snuff it.


Does it go away when you put it in reverse? In reverse, the L/R band holds the drum so it won't spin inside that roller clutch.

Thanks for the reply - It does not go away when in reverse, only goes away in neutral or sometimes park temporarily. How is something like that checked? not familiar with the part or most things transmission related

 

[hear]

Thanks for the reply - It does not go away when in reverse, only goes away in neutral or sometimes park temporarily. How is something like that checked? not familiar with the part or most things transmission related

The overrun clutch is literally the furthest component inside the trans; you can’t inspect it w/o disassembling the whole thing (which honestly is was less hard than you think).

But that was just my initial guess. When you’re just idling in gear, nothing inside the trans is rotating other than the pump & torque converter, but that’s happening in all gears…

The only difference is that in neutral no clutches are applied, but I can’t think of what might cause these symptoms.

 

[Jimmy's Jeeps]

Hi, did you ever solve it? I have a similar thing happening and am getting to wit's end.