Transmission Progress!

After I completed the detent repair on my transmission, it was time to prepare to re-install it. First up was rebuilding the shift mechanism, which basically involves replacing everything that isn't metal. Not hard, and I had ordered the parts months ago. The time-consuming part was just cleaning all the grease and gunk off.

Interestingly enough, what I found as I removed parts was that they were nearly brand new. I suspect the prior owner tried to fix the shifting problems by rebuilding the shifter. I did it the right way!

I had a decision to make about the clutch. I was having no problems at all with the clutch, and when I disassembled it, it seemed in good shape, and the clutch disk (the part that wears most) had a lot of "meat" left. The spec was a minimum of 7.5 mm, and I found an Internet post that suggested a new clutch was 9.2 mm. Mine was 8.4 mm. I decided to put it back in - it has probably 20-30,000 miles of service life left:

I did replace the throwout bearing, and the tube that it slides on, since that had some obvious wear. I replaced the bolts that hold the clutch pressure plate to the flywheel too. The new factory ones came with thread-lock compound already applied. And I replace the "guibo" - the big rubber donut that connects the trans to the driveshaft. The old one had a network of hairline cracks in it, so that was an easy decision:

The X-brace that I had removed was in good shape, but had some scrapes that had started to show a little surface rust. I put two heavy coats of POR-15 on it. That super-hard rust preventative should keep it safe for years to come.

Since we had SOOOO much trouble removing the old bolts holding the trans to the engine, I bought all new bolts from BMW. That cost a few bucks, but it was worth it in peace of mind. I also bought a set of "thread chaser" taps in the metric sizes needed, and used them to clean and re-form the threads in all those holes:

Finally, it was time to re-install. Kelly came over (and was witness to the negotiations for the new parking lot surface), and we got busy. I had started the clutch installation, but waited until Kelly was there to install the new bolts and torque them to spec. I was afraid that I'd need him to keep the engine from turning while I torqued the bolts, but it was all OK.

Then, we used the transmission jack to lift the trans, and inserted a couple of the biggest bolts to pull in in place. All was going well, but then... a setback. I noticed that a cable was in danger of being pinched, so I asked Kelly to reach way up in there with the socket extension bar and push it out of the way. When he did, a little adapter on the end of that bar popped off, and disappeared somewhere. We tried for half an hour to reach it without success, and then did the right thing and removed the trans again. Then we could reach the little recess it had fallen into and retrieve it.

That was a bummer, but we were actually in a good mood after we found the adapter. We had done what needed to be done, and the project was back on track. But we were both exhausted - it is very strenuous to work under a car with not quite enough clearance, lifting and straining and working above your head. We just didn't have the physical stamina to get that trans back in, so we left.

Kelly wasn't available again for another week, and I was busy the next night he was available, so I asked Troy Nace, my friend and colleague at Lancaster Church of the Brethren, to help. Troy is 25 years younger than I, and much stronger. We went over this afternoon, and got off to a great start. Here's a picture looking up from the front - you can see the flywheel teeth, clutch and the trans with the input shaft in the center:

I checked the clutch alignment with the alignment tool, and it was still perfect. We aligned the trans, and I rotated the guibo until I felt the splines on the input shaft engage the clutch disk. Then Troy gave a push from the back, and the trans slid right into place. Then we could do the arduous task of installing all the bolts. They were just as hard to reach as when Kelly and I removed them, but the new bolts and the newly "chased" holes made reassembling the bolts much easier than extracting them.

Then, we installed the shifter and the transmission crossmember at the rear. The trans is in! And testing the shifter in the car, the shift lever now centers correctly and engages all gears. A good afternoon's work. Thanks, Troy!

There are still a number of small items to install and check, and I must remember to refill the trans with gear oil. Then the driveshaft and exhaust system can go back on, and it will be time for a test drive!