weird noise never heard before, need done help diagnosing

Tampateggie89

New Member
weird noise never heard before, need some help diagnosing

Hey everyone,

New car, super excited, unfortunately I found an issue.

When driving in 4th gear under acceleration (60mph) sounds like a s*** ton of mechanical rattling, when showing my friend, he said transmission (yet he doesn't know manual transmissions) it also occurred today at 40mph in third, I did have a mechanic diagnose it (drove it) who said he faintly heard it and didn't think transmission, he thought wheel bearing or possible tire balance yet the tires are brand new...
I'm mechanically inclined but gong insane with worry over a simple fix...or a transmission.

The car drives and pulls great, very quiet idle, some heat does leak into the cock pit through the floor area, no real vibrations, car ran great until the noise which started in fourth.

Thanks guys!
 
Last edited:

Tampateggie89

New Member
Tampateggie89 said:
Hey everyone,

New car, super excited, unfortunately I found an issue.

When driving in 4th gear under acceleration (60mph) sounds like a s*** ton of mechanical rattling, when showing my friend, he said transmission (yet he doesn't know manual transmissions) it also occurred today at 40mph in third, I did have a mechanic diagnose it (drove it) who said he faintly heard it and didn't think transmission, he thought wheel bearing or possible tire balance yet the tires are brand new...
I'm mechanically inclined but gong insane with worry over a simple fix...or a transmission.

The car drives and pulls great, very quiet idle, some heat does leak into the cock pit through the floor area, no real vibrations, car ran great until the noise which started in fourth.

Thanks guys!
Click to expand...
SeanDA9 said:
Does it sound like this. https://www.youtube.com/watch?v=Rrb62jTBHTo
Click to expand...
It's not as electrical sounding, and there is no pause unless I drop speed
 


DCiFound

SEAHAWKS!!
SirClints said:
Are you sure its not the heat shield over the cat?
Click to expand...
Agreed. Check for rocks pebbles lodged between heat shield and exhaust. Use compressed air to blow it out or remove heat shield and remove pebbles by hand
 


Tampateggie89

New Member
DCiFound said:
Agreed. Check for rocks pebbles lodged between heat shield and exhaust. Use compressed air to blow it out or remove heat shield and remove pebbles by hand
Click to expand...
I'll definitely check the heat shield today, but it's coming from the front end, almost sounds directly from the engine/floor boards
 

Tampateggie89

New Member
Update: just did 70 in fourth, heard nothing... I think it's because I was trying to make a vidya for you guys, the activity of record might have fixed it.

I'm going to try again around 3ish and see if I hear it then
 

Merlins Beard

*Beard not included
If any of the lines under the car have been replaced they could rattle.
Although pretty unlikely as the cause, a lightweight flywheel and high performance clutch can cause 'transmission chatter' which can sound like a rattle and is due to the harmonics of the flywheel and clutch.
 

Tampateggie89

New Member
I've used the knowledge of a guy I work with, he was a mechanic for years, said it could be carbon build up on parts of the engine rarely used, which I did get it from ybor so it was a city car for the most part, the owner didn't have a license for a while so rarely drove it, to me this makes the mossy sense so far, he said it could be the shifter forks rattling on each other.

What do you guys think
 

Merlins Beard

*Beard not included


Looking at a picture of a trans without the bell casing, it looks like there is potential for them to contact at the center fork and the rod for the right fork, but I can't say for sure.

To me, that points towards something being bent or worn out with the shifter forks, which I imagine would cause shifting problems like grinding or difficulty getting into a certain gear.

However, the fact that this usually occurs in 4th at a certain rpm and vehicle speed supports that it could be the forks due to their position in that gear.

Rattling heat shields and brake lines occur at a certain rpm independent of vehicle speed, usually around 2500-3000 rpm. The fact that there is no noise in some gears points away from these as the cause.
 

Tampateggie89

New Member
]
Merlins Beard said:


Looking at a picture of a trans without the bell casing, it looks like there is potential for them to contact at the center fork and the rod for the right fork, but I can't say for sure.

To me, that points towards something being bent or worn out with the shifter forks, which I imagine would cause shifting problems like grinding or difficulty getting into a certain gear.

However, the fact that this usually occurs in 4th at a certain rpm and vehicle speed supports that it could be the forks due to their position in that gear.

Rattling heat shields and brake lines occur at a certain rpm independent of vehicle speed, usually around 2500-3000 rpm. The fact that there is no noise in some gears points away from these as the cause.
Click to expand...
Got it on video
[YOUTUBE="http://youtu.be/OMKo6ZC1aH0"][/YOUTUBE]
 
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