Time for a major update:
One year and 8000 miles since I finished the motor swap, and not a single issue, until about 4 months ago when I started hearing what I thought was a noisy release bearing. When I pushed in the clutch pedal, it would make some kind of grinding noise. I monitored it, and the noise was steadily getting louder day by day. To postpone the inevitable, I tried limping it along by speed shifting, and not keeping the clutch pressed it at intersections, etc. (The reason I do this is because I can't stand the gear chatter when it idles in neutral.)
So after about 2 months of this, I was heading out one morning, got to the bottom of the street, and BAM, it sounded like all hell was breaking loose inside the bellhousing. I turned around and parked it in a strategic spot in the garage with lots of room to work around the car, knowing that it wasn't coming out until the transmission had been replaced. I have always said that if it ever came to pulling out the transmission, I would upgrade to one with better ratios along the way.
A few days later, I started digging in to it. It took 2 days to actually get the transmission removed. It's a pretty labor-intensive process, especially when you don't have a lift. Anyway, I discovered that it wasn't the release bearing or pilot bearing that was making noise, but a strap which had broken on the pressure plate. It proceeded to flop around inside the bell housing and left some pretty nice grooves, and lots of "sparkles".
After a lot of back and forth on which transmission to use, I ultimately went with a 01A from a '89 90 Quattro. It has the same 4.11:1 final drive and 1st and 2nd gears as my old one, but roughly 10% higher 3rd, 4th, and 5th. Still not great, but a step in the right direction. Also, in an attempt to put an end to the noisy gear chatter, I purchased a dual-mass flywheel from a '93 Audi S4 application. Interestingly, it uses a solid disc. Since I never abused the old clutch, I suspect that the high compression of the diesel engine is what ultimately lead to the pressure plate failure. The DM flywheel should hopefully help to dampen things out, and save the new PP from a similar fate.
In preparing the new transmission, I had to swap on the 108 mm axle flanges from the original box, since the "new" box had 100 mm flanges. I also replaced the input shaft seal, the 3 output shaft seals, and various o-rings here and there. The original rubber transmission mounts had also started cracking, so I ordered new ones. I’m also doing the slave and master cylinders "while I’m in there".
This work to the tranny required the purchase of many new application-specific tools. I have gathered quite a large assortment now, and have decided to start a little side business renting them out.
Hopefully I'll be driving it again by next weekend.
Offending pressure plate.
Original box completely covered in grime. Still, it was amazingly clean on the inside. I chopped off the input shaft to use as a pressure plate alignment tool, instead of using those cheap plastic tools that are usually included with a clutch kit. Before I scrap it, I also stole a couple more parts off of it like the axle flanges, senders, torsen diff., front diff., and front diff cover.
Parts and new tools:
"New” box cleaned up, filled up with fresh Motul, seals replaced, and ready to go:
New flywheel installed and inner CV cups cleaned up:
