So I was right on the money!
Indeed an exploded disk!
This is what 200k of extreme abuse and horrendous day in day out Melbourne peak hour traffic does.
On a side note, these OEM thrust bearings hold up like NASA built them. Was still working fine and the plastic had stuff all wear.
The gearbox was good but also worse than I thought.
The rear main and front pocket bearing race surfaces were toast, some sort of debris in it's previous life ruined them. The chirping noise was for certain this.
Not just 2nd synchro was worn, but all of them except 5th was nearly bottoming out, so totally stuffed even though they felt good except 2nd.
2nd sync teeth were stuffed, that was me clashing them often. I didn't have half and hour to wait for it to engage
Input shaft teeth had some metal layer built up on one side on one half of the gear. I believe this is wear/debris metal that had cold welded to the teeth under the enormous loads.
The input shaft on one side was rubbing the inside of the nose cone from the flex due to the disk vibration, it also loosened the spigot bush to the point it felt out of the crank with the finger.
The pocket in the input was also pitted, I gave it a once over with some wet and dry but was not happy with the amount of pitting. So I used another input shaft I had that was all good in bearing surfaces but the 4th sync teeth were worn due to the donor that it came from had non existent sync rings at that point. But hopefully should be ok.
The counter shaft was in great shape as was the main and most of the gears, except 2nd.
5th is in great shape and is the best I have seen for a T5.
All of the sync hub springs were mostly worn through from the keys, so it's had some Ks! it was a mystery box that now has 200k more. Wouldn't be surprised if it's got 500-600k now.
All else it was very clean inside and certainly not terrible for unknown previous life and lots of ks.
So I started to cobble together a decent box with all the random ok and some new parts I had and new bearings.
I used a pressure washer to clean all the parts and assembled dry where I could. It's the best way to eliminate dust and insects getting stuck and also allows me to air gun the case as I go to maintain dust free.
As for the counter shaft retaining plate. I won't be using any of the billet ones in this shitbox but I had 4 sets of shims and plates and none of them in any combo was any better than 0.5 to about 1mm end float.
I concluded that they were all set this or very loose from factory. The later tremec built ones tightened up this spec to 0.013 to 0.102mm.
So I had to take the best combo and wet lap it on the concrete. Eventually I got 0.02ish mm float and once I added a little ATF to the bearings it felt and sounded really good.
Got all the lower bits done and started on the main shaft.
A good trick once you get a gear and it's shims and bearings sorted is to cable tie it all together so you don't lose track of the order and visually it's easier to know which group of parts goes on the shaft next and in which direction.