Anyone want to guess...

[DogRocker]

...what this noise(s) could be in transmission?

https://youtu.be/VV13Bo94964

To me it sounds like a bearing noise at around the 0:13 mark in the video. There's also a lot of general whining noise, but that may be normal(?). Dunno.

The rattle noise heard loudest at 0:13 point happens whenever I accelerate moderately in any gear. That is, climbing grade, flat or downhill at any RPM it'll happen when I accelerate, that is increase the load.

The fluid was recently changed to GL1 type.

Any guesses?

[wubie317]

I have a somewhat uneducated guess...Because the sound occurs under load, I'm guessing it's the differential. Mine is also making noises, and my mechanic has told me it will eventually go completely. I have heard the pinion can be replaced (don't know how difficult a job that is), but if the diff's guts are on their way out, it'll need a full replacement.

[DogRocker]

Thanks for the response.

I don't think it's the diff. This past October I had the Diff checked with new oil and gasket installed by a Fiat Master (Ray at http://performanceapex.com/index.html). I had taken the car to him for some front end work and a general "once over". He initially discovered the transmission noise while test driving it but couldn't quite pinpoint it. While he had the car I had him remove the transmission case cover, do a visual inspection and change the trans oil. He mentioned that the oil that came out didn't seem like the factory recommended GL1. At this point, I'm guessing the previous owner may have been using a different oil to quiet things down. Don't know, and it don't matter now.

He also replaced the drive shaft support bearing.

The noise is definitely coming from the transmission area forward of the shifter.

Since this initial post I pulled the transmission cleaned it a bit, and just started taking it apart. There was a some fine brass(?) dust in the gear oil and bottom main housing cover. Syncro material perhaps. Strange, because it seems to shift fine. The picture below is about 20 miles of driving on fresh GL1.

Also, the Input Shaft seems slightly loose to me. If I move the Input Shaft I can see the Input Shaft gear wobble a little bit inside the gear box which moves the Syncro a bit too. I'll be replacing the Input Shaft Bearing for sure. To my ears the rattling sounds like it may be a needle bearing type assembly like the one on the end of the Input Shaft. This is pure guesswork right now, as I have little recent wrenching and zero transmission experience. Regardless, I'm really excited about working on this gearbox for some reason. Strange.

[SeattleSpider]

Ray's the best. Surprised he could not pinpoint it.

[BEEK]

I have built 100's of these gearboxes. That is an excessive amount of brass. thats like 30k miles worth of wear. You may have a bearing problem and a gear mesh problem. I would disassemble the gear box, it is already out. the hard part is done. Take it apart and the culprit will be very evident.

[DogRocker]

"Ray's the best. Surprised he could not pinpoint it."

I can't really fault him. He understood the transmission needed to be taken apart. Btw, his wife Laurie seems very knowledgable too as well as extremely nice. They're a great team. If I didn't have such a strong interest in taking this apart I'd be taking the transmission to him.

"...Take it apart and the culprit will be very evident."

I hope so. I'll post pictures here. They may be helpful to others as well.

[Nanonevol]

I think the input shaft carries fourth gear. Mine was worn on the end so I replaced it along with many other parts.