240Z 4-Speed Transmission Noise

[marvelous240Z]

Can anyone help identify the noise coming from my 240Z type "b" 4-speed transmission. Attached is a video. As you can hear there is a rattling that slows and comes to a stop when I depress the clutch pedal. The rattle speeds up at the end of the video when I give it some throttle in neutral. The transmission also sounds a little raspy through the first couple of gears. Don't mind my high idle I still needed to tune the carbs when this video was shot.

Some background: Don't know if it matters but my 5/71 was supposed to come with a type "a" 4-speed but one of the previous owner swapped it out with a type "b" for reasons I don't know. I also know the previous owners "friend" swapped out the clutch which my shop confirmed was new. Not sure if he took any shortcuts when he did so. The car was recently restored and I can't remember if the noise was there before I dropped it off. It came from CA to NY and I didn't get to drive it much before I started to disassemble the car. There was a similar video posted by a NY z club member and the issue turned out to be a loose flywheel bolt. My shop picked up the car after I showed them the video and they brought it to their transmission specialist. He first suspected that it may be a chipped tooth on one of the gears but after he opened up the rear housing everything looked to be in good shape. Does this sound like a flywheel or clutch issue?

<iframe width="960" height="720" src="//www.youtube.com/embed/vBG6JJpFDlw?rel=0" frameborder="0" allowfullscreen></iframe>

[EuroDat]

Thats a strange noise or my smartphone is distorting it.

Does it make this noise when you drive it? The reason Im asking is Im just trying to eliminate things like the needle bearing between the input and output shafts. If it does not make the noise in 4th, that could be it.

If the flywheel is loose, depressing the clutch will push it back against the crankshaft and reduce or stop the noise. Sounds feasable. You could check it by taking the starter out and checking the flywheel for movement. Rotate the engine to different positons. If some bolts are still tight you might miss it.

Chas

[Travel'n Man]

Bearings - time for a rebuild. Exact same challenge and noise for me with my 5 speed last month - rebuild fixed it right up.

Edited October 13, 2013 by Travel'n Man

[marvelous240Z]

What bearings? The rear housing was taken apart and spun by the transmission shop and they said everything was in good shape.

[beermanpete]

The input shaft bearing, pocket bearing, and lay shaft bearings are all in motion in neutral. You cannot see these from the tail shaft side to inspect them. You need to pull the front housing of to inspect these.

[PastorMike]

My transmission had the same symptoms.

Rear bearing on the counter-shaft; the

ball separator was coming apart allowing

the balls to re-position within the races.

[Travel'n Man]

Most the time with these type noises the bearings have to be pulled to "feel" what is in default - at that point it is just as easy to replace all of them while you are at it.

[tlorber]

Have you found any pieces of the bearing races on the magnetic drain plug?

If you crack the tranny open to replace the bearings, you should check the baulk rings. If you are going through all this (a tranny rebuild) you might look into a 5 speed swap from a ZX. You'll have a different car.