grinding noise from transmission/engine
 

So I took the z in to get a misfire (turns out it was a loose connector) and i got it back a day later. I drove it off and heard a grinding noise, or 2 pieces of metal rubbing together. It would start when i drove in first and got less and less as i went through the gears. I could rev up and the rpm would climb but i wouldn't accelerate much. The grinding noise would go away in the morning, but later in the afternoon it would come back. Also the fuse to the radiator fans got tripped when the sound got really bad. I could feel it in the gas peddle when accelerating. It felt like the clutch just wasn't really engaging right. so i took it back to the shop and they said to replace the clutch and flywheel and they went ahead and replaced them with oem parts. It worked perfectly for a day, then the grinding started coming back. A little at first, then back to normal where it felt like something was about to break. Yall got any idea what this could be? I took it to the nissan dealership to let them take a look and forgot to get any sound clips.

Note: no codes were thrown

Did the repair shop replace your throw out bearing when they did the clutch and flywheel?

yeah.

Replacing the clutch and flywheel worked briefly and then failed. That tells you it is a problem with the clutch, one of it's components, or the throw-out bearing... or could it be the transmission? Some of the early 350z transmissions had problems (mainly with the synchromesh, which cause a lot of noise -- grinding noises).

My guess is its something with the tranny. I can put it in neutral and rev it and it doesnt grind. Only in gear

Your description points to a problem with the throw-out bearing.

solved it. Its due to some worn down parts in the transmission. The mechanic said years of someone not using the clutch to shift.

Thanks for posting the resolution to the problem. That helps us learn.

RE> "The mechanic said years of someone not using the clutch to shift." That would definitely damage the throw-out bearing.

He said it wasn't the throw out bearing, but actually some roker arms. He drained a bit of the transmission fluid and it was full of bronze chips and shavings. Luckily, the transmission isnt going to destroy itself because of it.

OK... :confused: There are no "roker arms" in a transmission.

Maybe he meant "rocker arms" (which are also not in the tranny either). Could have meant shift rails, which are a part of our gearboxes.

Yes... This is confusing. Rocker Arms are inside the engine and could cause the "chips and shavings" his mechanic describes, but that would be in the engine and not inside the transmission. :dunno:

I agree with you about the terminology confusion, but "Shift Rails" are not close to "Roker Arms."

Probably not what it is then. It was over the phone and i wasn't really paying attention once he said it wasn't that big of a deal.

I must tell you that this is probably the worst thread started on my350z.com.

I changed recently the whole set with a Z1 Fluwheel and clutch kit and a new OEM throw-out bearing came with it...and the noise is still there....in the morning on a cold start when I let off the clutch and during a first morning drive through all the gears...even the mechanics are confused but if all the components in the clutch are new( and I hope properly installed)...guessing the gearbox should be the problem..especially in my case 'cause I got a 04 crappy syncro 6speed :(