Transmission Noise?

[The Horvaths]

So, after starting my car (mostly when cold), something makes a metal-on-metal grinding noise while it up-shifts. This is especially prevalent under heavy acceleration. I noted that the trans had a small block dust cover, (The transmission is a 727 TorqueFlite mated to a 383 BB). The old dust cover was eaten up, (it showed signs of striking the flex plate), and we replaced with the correct BB cover. It still makes noise. After shifting to third, the noise is gone, and does not happen again until restarting (Starter related?). Any ideas would be appreciated.

 

[Wollfen]

Sounds like you might have a cracked flex plate which "tings" under load. Without actually hearing the noise i can only guess as to what else it may be.

 

[The Horvaths]

So, we are thinking that the problem might actually be detonation. We turned down the timing, and it seemed to help quite a bit, but it was warmed up. We think it may be the vacuum advance being too sensitive. But, the question is, why does it only happen when it is cold? Could the vacuum be higher when it's cold?

 

[65sporty]

Detonation usually is worse when the engine is hot and under a load, backing off the timing and road testing will tell you if that is the problem

 

[The Horvaths]

Mever nind! The stinky chopped up fan shroud on the stinky aluminum radiator was hitting the fan blades. Spooty modified machine!

 

[68plymouth383]

A pair of new motor mounts wouldn't hurt. Seeing how it does it while driving when heavy throttle is applied...

Mever nind! The stinky chopped up fan shroud on the stinky aluminum radiator was hitting the fan blades. Spooty modified machine!