So a couple of weeks back I replaced the 3-4 synchros/sleeve on my s4c tranny and I also added a an LS 5th gear. While I was putting my tranny back together my isb fell apart and I managed to get it back together and continued putting everything back. I have since put about 1000 miles on the tranny. Just this past Monday I notice it was getting harder for the gears to go in an was getting a hissing-metal rubbing sound from the trans area. I pulled the trans apart today to find that some of the ***** on the isb were pitted and also found some synchro shavings. All my syncros are in great shape with the exception reverse syncro and collar they are frozen together and you can see some heat discoloration on the collar. The 5th/reverse sleeve gear has signs or heat discoloration and looks like the collar was rubbing on it.I also noticed that if I held the clutch in the hissing would go away but the car felt like it was in gear and would not roll back on my driveway. It also felt like I had the handbrake on when I would try to take off from a stop.

Any idea what I did wrong that caused this to happen?

 

Why did you not replace the ISB that fell apart? That was a mistake. Did you take everything apart and clean it thoroughly? Dirt and debris (pieces of broken bearing cage especially) will plug up the oiling holes in the main and countershaft starving parts of the transmission for oil. I'm not sure if that's what happened in your case, or if something was shimmed wrong or if it was some other type of assembly problem. That hub in the top picture is junk, the sleeve looks good, but if it's discolored it's probably soft as butter and wont last Replace the needle bearings in that area along with anything else, including gears that are discolored.

 

The damage was caused from misalignment of the reverse stopper plate. When the plate is not clocked correctly, the case will not fully close by hand and when the bolts were tightened it smashed the 5/R hub and synchro.

 

Thanks Synchrotech got all my parts from you guys and was able to put my tranny back together with no issues this time.

 

Glad we could help