Transmission Sound???

uestraven

Daily Driver
Nov 13, 2011
27
0
0
Long Island
So im posting this in transmission technical because thats where I think the problem is coming from. I have a chevy 350 mated to a stock TH350. Earlier today the motor was running just fine. Not a single problem. Out of nowhere I started hearing a very loud clanging noise. At first I thought it was the header shaking violently. I literally checked everything I could, headers, valvetrain, starter, exhaust, pulleys, carb, you name it. I then noticed the noise went completely away the second i gave it gas. So it only came during idle. I looked under the car and saw that transmission fluid was leaking from between the converter and transmission so I figured I blew my front pump. Would that have caused the clanging sound?
 

uestraven

Daily Driver
Thread starter
Nov 13, 2011
27
0
0
Long Island
I checked the flexplate. It definitely isn't loose and it wouldn't explain the leaking fluid
 

LS6 Tommy

MalibuRacing Junkie
May 15, 2004
15,847
1
38
North Jersey
I think the Turbo Encabulator went bad...

#-o

Sorry... Couldn't resist. I would have thought flex plate, too, except for the leak... Does the crank move forward & back if you thump the center of the balancer & flex plate with a rubber mallet? Maybe there's excessive thrust & it isn't a trans leak but the rear main seal...

Tommy
 
You can't verify if the flexplate is cracked unless you remove the transmission and torque converter. Flexplates most commonly crack around the bolt holes where they attach to the crankshaft. There is always the possibility that the source of the noise and the leak are totally unrelated. You're going to have to remove it anyway to repair the leak. Torque converters and front pumps don't generally make a clanging or knocking sound when they fail. If you pull it all apart and don't find any problems in the pump then you're still going to need to replace the front pump bushing. Leaks from the front seal generally aren't a seal problem but are actually most commonly caused by a pump bushing that has failed or that is worn excessively. You're also going to need to inspect the torque converter pump hub for excessive wear and/or an out-of-round condition.
 

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