Ticking/rattle M45 VK45

[Amgberg]

This rattle is killing me because can not find the fix or problem its not the heat shield not the Y pipe not injectors not bad gas. It's on the left side of the engine. Start up it its a light rattle rev the rattle gets louder. Sound is loud when car is cold but In between shifts the sound dies and once in next gear sound return I'm starting to think it's actually the transmission? Idk. It's just her annoying. Hard to explain the sound it sound like a heat shield rattle but it's clearly not because I removed all heat shields. I feel like maybe as the transmission warms up the sound gets less noticeable. So thinking maybe it is the trans I don't know lol geesh!

[svard75]

If it's rattling while in P I'm thinking it's more the infamous v8 knock

just-bought-a-clean-06-m45-that-needs-a ... 87558.html

[Amgberg]

If it's rattling while in P I'm thinking it's more the infamous v8 knock

just-bought-a-clean-06-m45-that-needs-a ... 87558.html

It's wierd because it don't seem to be ending knock, yes in park your hear a very low rattle as it warm up the sound fade away but still present. If you drive it cold the sound drop when gear change. I know valve chatter but it isn't valve chatter. I took the heat shields off the y pipe. So now I'm gonna take the heat shield off the primary cats and headers. And the thing is I seen many other m45 with the same noise but maybe the sound doesn't bother the owners but it bothers me it's annoying. Thinking maybe the transmission fluid is low?

[svard75]

If the fluid levels were low you would have problems with shifting. Ticking and Grinding from the transmission would indicate something far more serious. I think you have a good process of elimination going here. Get your hands on a automotive stethoscope and use that everywhere to isolate the rattle. What about the spash guard underneath the car? The heat shield that is welded to the actual body? Is your engine mount damaged in such a way that the motor rotates more than it should and therefore the exhaust is striking the body? These are quite unusual but something to also check.

[Amgberg]

If the fluid levels were low you would have problems with shifting. Ticking and Grinding from the transmission would indicate something far more serious. I think you have a good process of elimination going here. Get your hands on a automotive stethoscope and use that everywhere to isolate the rattle. What about the spash guard underneath the car? The heat shield that is welded to the actual body? Is your engine mount damaged in such a way that the motor rotates more than it should and therefore the exhaust is striking the body? These are quite unusual but something to also check.

Thanks for the help. So I check the mounts and looked pretty solid I found a shield that is over on top of the engine mounts but didn't seem to have a issue. Now lol this was very odd, I put the scope on the side I would hear the noise then put it on the other side of the engine. One side of the Engine is clearly louder than the other! The rattle is on the side of the engine like if you sit in the car it would be on the driver side.

[svard75]

So is it the upper part of the engine where the ticking or rattling is occuring or bottom end?

[Amgberg]

So is it the upper part of the engine where the ticking or rattling is occuring or bottom end?

Seems like around the middle like exhaust manifold area it's not the top so I would say middle running down exhaust manifold area. I will try cutting off the shield on the primary cat

[EdBwoy]

Loose precat material maybe? Does it come with a check engine light or pending codes?