what would cause this?

[73chargercali]

i recently noticed a grinding noise when i slow down from about 30mph to 20mph not above or below. it sounds like transmission. i checked bolts and they were all tight but when i push up or grab the drive shaft and shake it there is noises rattling in the transmission??? sounds like metal moving and then a thud, its fairly loud. is this normal or what would make this noise? the trans is only 7months old.

[John_Kunkel]

Did you check the flexplate-to-converter bolts?

[Bandit72]

cracked flex plate?

[TylerCharger69]

I'm going to guess  a backed out  torque converter bolt...(supposed to use Loctite on these)  or a cracked flex plate....I'm with the majority opinion in this one

[73chargercali]

so i cant get it to move anymore and it makes a rattling noise still. it now sounds like a loose heat sheild or sheet metal. i'll check the flex plate and converter bolts when i jack the car up. thanks for the help.

[Todd Wilson]

Not ruling out any of the above ideas or suggestions. They are what to check first most definately. 

A few years back I had a noise problem. Kinda a grinding noise. Coming from the transmission area. I checked everything I could think of. Thought it was maybe the rear end causing a harmonic vibration up to the tranny.   It ended up being the pulley on my AC compresser. The bearing was making the noise.  It was a harmonic vibration but it came from a place I never even thought to look. Funny thing was I could not get the noise to happen when idling. Only when driving. Took off belts and would make a trip around the block and discovered it. Ifyou spun the pulley and it was quite you could hear the same noise just not amplified.

Food for thought on your chase to figure out the noise. It may or may not be what you think.


Todd

[73chargercali]

it was both the exhaust collectors, i guess the vibrations just rattled two of the adapter bolts loose. thank god it was any thing major.

thanks for the help everyone.