Sam95ZNoTop

I posted my question in an older thread about a Street Twin install, since they ended up with the same EXACT problem that I had after a stock clutch replacement and T56 rebuild. I guess noone sees it because it mentions a Street Twin clutch in the title. Maybe a new thread will get more attention.

The thing that happens is a vibration/rattle in 3rd and 4th gear only, and then only at 2k rpm when you're giving it a somewhat higher load. It dissappears when the rpm goes over 2300 or under 1900...

This is what was done to the car: It started doing this vibration after I took it to a transmission place because it was grinding badly when you slow down for a stop and you downshift into a lower gear. It was also making the classic pilot bearing noise. They basically did a rebuild on it: new bearings, synchros and a new 1-2 hub and slider (those were probably making the noise I was hearing before the rebuild). I also provided a new Advance Auto Parts clutch (same one as from Autozone, basically a stock replacement) This clutch disk has springs in it, just like the stock one. They used the pilot bushing and not the bearing to install it. They also replaced the rear main seal while they had the clutch off (doesn't have anything to do with it, but I just want to be complete, just in case).

After the rebuild the downshifting noise was gone, as well as the pilot bearing noise. It shifts great, the clutch holds great, does not chatter (after break in period). The ONLY thing that is wrong with it IMO is the vibration/rubbing in 3rd and 4th gear, and then only at 2k rpm when you're giving it a somewhat higher load. I drove it like this for about 2000 miles and just recently took it back to the shop that did the rebuild (had a 12month warranty on it). They took it completely apart and checked everything, then replaced the 3rd gear synchro, just to try, thinking that may be it. Also checked the clutch, nothing wrong there either. Then put everything back together, and NOTHING has changed, same EXACT thing still happens. They also looked at the motor mounts, U-joints on the driveshaft, and could not find anything wrong there. They have no idea what it could be, but assured me nothing inside the transmission is wrong, so, whatever it is, it shouldn't cause any damage there...

So what could be causing this? I do have springs in the clutch, so it's not rigid like a Street Twin (where other people have had this happen). Unless I compress them completely when I accelerate a little bit stronger? What do you guys think?

Thanks in advance!

Sam

Sam95ZNoTop

I keep getting replies under the ST thread, however they are ALL related to the ST clutch...

Nobody any ideas on what would be causing the noise!?!?

Thanks!

Sam

Sam95ZNoTop

Does someone at least have an idea?

Thanks!

Sam

My94RedZ28A4

Sounds exactly like a problem I had with my Manual S-10. It ended up being a U-Joint. My advice would be:

1. Try unbolting the driveshaft and rotate it 180* and bolting it back. If that still doesn't help (or if it makes it worse)

2. take the driveshaft to a shop and have them press out and press in some new ones. I bet that it will fix the problem.

Sam95ZNoTop

Sounds like that could be it! That's the only thing that has not been replaced/checked and it did get unbolted and rebolted during the rebuild obviously... I'll see when I can try that!

Thanks!

Sam