squealing sounfds from AT?

[mikecrowell]

I'm somewhat baffled at what this new found sound could be. It is a high pitch squeal (not too loud, yet) that I just started hearing. It happens at times when the Automatic transmission is "shifting" through the lower gears, around 2200-2300rpm's, but I've also noticed it at higher gears and rpm's.It's noticeable from a few seconds before the the A/T goes into the next gear, through a few seconds after. Initially I thought it would be belt slippage( sound is very similar), but it is not evident when I accelerate to the same rpm's in Park. I also thought it could be some sort of whistle noise from the air intake, but again, I should notice this when in park. The transmission fluid looks fine. Anyone have an idea? I'm thinking now that maybe I should definatley rule out the belt(s) with the soap trick. Any other thoughts would be appreciated. I've only had my Explorer for about three weeks (and still have a dealer warranty)so I hope this is not a major problem.

 

[Mike R]

I have a 96 that does the same thing I thought to it was the throttle plate whistling and it seems to only do it when the engine is under load.I can let go of the gas a little and it will stop or I can give it a little more and it quits also.I think it wont do it in park because of there not being any load on the engine?,just some thoughts let me know if you figure anything out! (96 4x4 75,600 miles)

 

[kilroy]

Is it a high pitched squeal, kind of like stepping on a dog toy? I had something like that on another car that I owned, and never could figure it out, but I put over 60K on it before I got rid of it, and never had a problem. The only thing I could think of causing it was the gasket in between the valve body plates vibrating when the fluid squirted past at high pressure and then quit when the pressure stabilized, kinda like when you hold your finger over the end of a hose and then let go of it.

 

[HIX]

I have a high pitched squeal that comes from the belt tensioner pulley. If you stick your finger behind the pully and into the back of it you will feel a spring. Obviously don't do this while the truck is running! On mine the spring rubs sometimes.

Just a thought

 

[mikecrowell]

O.K. I have not figured this out but the sound is starting to drive me nuts!!! I've tried rubbing soap on the belt, did not help, and again, this only happens under load, so the belt should still make the noise in park, right? It's getting more noticeable over the short time I've owned this vehicle. Any other ideas?

 

[pistol_fish]

This is not a belt problem. see thread called "whistle under hood"