Rattling sound around trans and exhaust

[JozefJ]

Hi guys,

Looking for some advice here..
I have a '73 Dart Sport, 318cui, a904 TF.
When I start the car the engine turns over and starts well.
However, there is a kind of rattling sound around where the engine meets the transmission, both at idle and while driving. The same sound I also hear around the end of the exhaust. There is no impact on acceleration, shifting or other things.

Ive checked the heat shields, ATF, but no anomalies there..

Can you help me figure out what it could be?

TIA!

 

[Locomotion]

Hi guys,

Looking for some advice here..
I have a '73 Dart Sport, 318cui, a904 TF.
When I start the car the engine turns over and starts well.
However, there is a kind of rattling sound around where the engine meets the transmission, both at idle and while driving. The same sound I also hear around the end of the exhaust. There is no impact on acceleration, shifting or other things.

Ive checked the heat shields, ATF, but no anomalies there..

Can you help me figure out what it could be?

TIA!

Check the flexplate for cracks.

 

[JozefJ]

Check the flexplate for cracks.

Is this a potential risk for safe driving? And can I do that without taking the engine or transmission out?

 

[340six]

If flex plate is cracked / broken you have to remove the trans. It bolts to the crankshaft and converter

 

[Oldmanmopar]

Does it sound like drive line to body or internal engine. Headers with rubber engine mounts?

Could also be loose flex plate to crank bolts?

 

[JozefJ]

If flex plate is cracked / broken you have to remove the trans. It bolts to the crankshaft and converter

Check. But can an inspection be done without removing the trans? I've read about an inspection hatch or something like that.

And does the flexplate also move while the car is idling?

I don't experience any problems while driving aside from the sound.. Could it be a big problem then.

 

[JozefJ]

Does it sound like drive line to body or internal engine. Headers with rubber engine mounts?

Could also be loose flex plate to crank bolts?

Its a sound both around the engine/trans link and also at the end of the exhaust. Both at idling and while driving. Doesn't seem to be coming from the engine.

 

[Kendog 170]

You can inspect the flex plate and bolts by taking off the inspection cover. Engine off look and check then partially, then turn motor and so on until all checked out.

 

[Oldmanmopar]

Muffler coming apart inside. Many time you hear this with cars that have bad catalytic converters.

Yes you can check the flex plate for cracks by removing the dust cover an turning the engine one turn by hand .

To check flexplate to crank bolts. With dust cover removed grab the torque converter and flexplate and turn it side to side . It should not have any loose play at all.

 

[340six]

You can inspect the flex plate and bolts by taking off the inspection cover. Engine off look and check then partially, then turn motor and so on until all checked out.

This. Pull battery cabel off at battery, then starter, then the inspection cover.

 

[H22A4]

Single or dual exhaust? Check to make sure the exhaust isn’t making contact with anything (ie: torsion bars, transmission crossmember, gas tank). Even if it’s not touching anything when the engine is off, if it’s close in some areas, it might actually be touching when the engine is running.

 

[Professor Fate]

Easiest things first.
Make sure the exhaust is not touching anything (or even close to anything) that would induce a rattle. If possible, get it up on a lift and run it and see if you can isolate the source of the rattle.
Second most likely is the transmission inspection cover. Frequently it is distorted (it doesn't take much, and is rarely even visually noticeable) and can come in contact with the torque convertor to flexplate bolts. This can especially be an issue with aftermarket convertor bolts, which sometimes have a slightly thicker head than factory bolts. To confirm, remove the inspection cover and run it. If the rattle is gone, carefully massage and tweek the cover until the rattle is gone.
If the rattle persists after the cover is removed, then move on to the next level as previously mentioned.

 

[j par]

 

[JozefJ]

Single or dual exhaust? Check to make sure the exhaust isn’t making contact with anything (ie: torsion bars, transmission crossmember, gas tank). Even if it’s not touching anything when the engine is off, if it’s close in some areas, it might actually be touching when the engine is running.

Single exhaust. Will check if there are any (close to) contact points

 

[Righty Tighty]

I chased a rattle for months in my '74, could not find it to save my life. Turns out it was a socket that had fallen and got stuck in the header collector.

Lesson -- don't forget to think simple, in addition to all of the above advice.

 

[Inertia]

Heat-riser valve on passenger side exhaust manifold .

 

[JozefJ]

Heat-riser valve on passenger side exhaust manifold .

This one I could easily turn around by hand, and the bimetal spring is very loose. I think I have found the (at least first) cause of the rattling.

 

[Kendog 170]

You could make sure it's open and tie it up with some wire unless you decide to replace.
Pardon Our Interruption...

 

[j par]

This one I could easily turn around by hand, and the bimetal spring is very loose. I think I have found the (at least first) cause of the rattling.

And the marble...lol...