General transmission diagnosis please

[Guest]

The subject is a Mopar A-727 3-spd automatic (formerly) mated to a 318.<P>I'm more of a manual sorta guy so these slushboxes are not my strong suit. Could use some guidance.<P>At least two different people have told me that I have a cracked flexplate. Josh and I finally got the transmission off and frankly the flexplate looks fine to me. What is usually meant by a cracked flexplate? Where is the crack typically?<P>Regardless, the symptoms are quite real. The truck makes a chattering noise dependent on rpm, which occasionally goes away at certain speeds, or loads, or in certain gears. I've had one starter replaced due to the bendix getting beat to hell by the ring gear. A while ago I went under there with a mechanic's stethescope and there is no doubt the source of the noise is the front of the transmission. And the noise has gotten a lot worse lately.<P>It appears that the flexplate acts in part in a spring sort of way, allowing for a certain amount of drivetrain movement. Is it possible that the flexplate is simply wore out and no longer doing its job properly?<P>Could something else be wrong that has the same symptoms?<P>Cheers,<BR>Bry

[Guest]

If your talking about your truck with a 318 look where it bolts on thats where one of mine cracked.At idle it was loud, step on the gas and it was quiet.<P>------------------<BR>Mike<BR><A HREF="http://1964cadillac.carsouth.com" TARGET=_blank>1964 Cadillac & Cars from the 40`s to 70`s<P>FREE! Cadillac parts posting</A>

[Guest]

Well the darn thing isn't cracked, no way. It is scored in a couple places and it's bent slightly -- a couple of the arms sit perhaps 1/16" off level. Think this small variance from spec would be enough to cause problems when spinning? Or is there nothing wrong with my flexplate and something else is broken?<P>Cheers,<BR>Bry

[Guest Hal Davis (MODEL A HAL)]

Guys, I'm a fixin' to show my stupidity. What's a flexplate? Is it the light weight "flywheel" that the torque converter bolts to? I realize that without the torque converter, it doesn't have enough mass to act as a flywheel. I just never knew what else to call it.

[Guest]

I didn't know either till it broke. But yeah you got it. Except on Mopars it doesn't even look like a flywheel -- it's a clover shape. Its only evident purpose is to provide a small amount of flex between the engine and transmission.<P>I noticed some parts catalogs also called it a "driveplate".<P>Cheers,<BR>Bry<p>[This message has been edited by Bry in Virginia (edited 05-12-2000).]