Ringing noise from 727 at idle
 

Hi,

I'm getting a strange noise from my trans at idle in gear. It sounds like perhaps an internal servo/piston is oscillating, and making a high pitched metallic rattle/ringing sound. It's been going on for a while and can't really associate it with any changes to my setup.

I originally thought it was the metering rods in my Edlebrock carb slapping up and down due to low idle vacuum. The trans has a transgo improver kit in it and I don't recall any issues at that time it was installed. The problems seemed to have started when a rebuilt 440 was installed about a year ago. It has a mild Comp Cams grind in it and all else is stock. Converter is a stock unit. Any thoughts would be helpful.

Thanks,
Rob
'73 B'Cuda 440/727

Weak PCV valve will make that sound.

But I would Grab an old stethoscope from Ebay and pull the head off and connect a piece of vacuum hose. It will definitely tell you where eactly the noise is coming from cause you can source the noise withing a couple centimeters.

I just used this to find a dry seal in a rack and pinion that had me chasing my tail for a while.

Never tried that sort of thing before. Good idea. Thanks PK!

It could honestly be a multitude of things...

As previously state, buy a stethoscope, very handy for diagnosing noise concerns.

Have someone sit in the car, foot on brake, e-brake on, tires chalked on both sides and in gear and probe around the engine and transmission.