Squeaking When Stopping

[nn2s2u]

I have a squeak coming from my 96. 4EAT trans and 2.2L engine with 190k.

 

 

 

 

• The squeak sounds very similar to a something in the braking system rubbing or scraping when stopping. I spent a day cleaning and the pads/rotors and shields because it sounded like that was the problem.
  
• Noise only happens when braking. It might be very faint when the breaks are released and coasting in gear, but it's not really noticeable. It doesn't happen under acceleration.
  
• After that didn't solve the squeak, I did some more testing and discovered that the noise only happens under braking, with the transmission in gear. If the transmission is in neutral while braking, no noise.
  
• If I put a fuse in the FWD switch, these is no noise at any time.
  
• ATF was last changed about 20k miles ago. Still looks normal.
  

 

What's making this noise? I think it's possibly the rear transfer case/switch in the transmission, but I sure hope not. I don't see how it would be any of the drive line components, because they still spin even when the 4WD is off.