I haven't driven the 'Bird since about September. Last time I drove her, she ran and sounded like a champ ... except for a tiny hint of an exhaust leak. Well, pulled her out yesterday (beautiful day) and went for a spin. Very noticeable exhaust leak from the driver's side header on start-up. Even more noticeable under load. After she was warmed up good, I put my foot to the floor, and a TERRIBLE ticking/clicking noise (almost like an electrical "popping" sound ... but also a little like grinding) came from what sounded like just below the radio console. So, I let off. Went home, let it cool down, then tightened the header bolts (which were loose). Went back out ... exhaust leak noise was completely gone, but when I put the hammer down this nasty sound started happening again. The car was running GREAT, so I had no idea what it could be. I got on a straightaway and hammered it again. Once it got past about 3800 RPMs, the sound went away ... but then when it shifted and dropped to about 3000, the sound came back.

Any ideas? Thanks!!

 

torque converter bolts coming loose? cracked flex plate? just guessing....

 

Do you have alluminum header gaskets? If so those have an amazing amount of crush to them. I have them on my camaro and I had to tighten it down, warm it up and tighten it while it was running (scary), turn it off tighten again immediatly just keep doing this until the bolts stop moving. Hopefully you have the lock washers on there which will keep the bolts from backing out.

If you do not have alluminum header gaskets I highly reccomend getting them. They are a million times better than the fiber gaskets and they have them at Kragens. Sometimes what can happen is a portion of the gasket will burn and fall out from one or more of the exhaust ports, still making it appear that the gasket is still in place.

 

Additional info: This ONLY happens when the car is in drive. I cannot replicate the sound in park or neutral.

 

May be the converter bolts backing out

 

ah well that defintely changes things. perhaps its time to swap to that 4L60E you've always wanted. lol :/?

 

That definitely sounds like an issue with the torque converter, since it only makes this noise under load, i.e. in drive. That confuses me though, with how it just goes away after 3,800 RPM.

 

Ah ... Pocket ... great to hear from you, man!

I will check the converter bolts. Figured that would be more of a "knocking" though. And, yes, it only happens under load AND only when the pedal is all the way down.

And as far as swapping to a 4L60E ... this 700R4 has less than 2,000 on the rebuild.

 

The converter tapping the flexplate makes a very strange sound. Ask me how I know

You've already got a 4L60, upgrading to a 4L60E on the TPI ECM is not a minor project

It'd also be a good idea to check various heat shields and other things in the vicinity of the exhaust. Cat shields do come loose, been there done that too