Transmission - DONE!

After the HUGE effort that Kelly Williams helped me with (parts 1, 2, and 4), along with Bob Zimmerman (part 3) and Troy Nace (also in part 4), along with some serious tool development and trans repair by myself in part 5, it was finally time to put everything together and get the car going again. John Zimmerman was the person who helped with the heavy lifting to finish the project in this post, part 6. What a project. Along the way, I wondered if all this effort could possibly be worth it, but now that everything is working and really, really improved I can say: YEAH! What a sense of accomplishment to get a transmission out that seriously didn't want to be disturbed, renew all that needed to be renewed, and put it all back together.


I did as much work as I could to prepare before John came last Saturday. Now that the trans was completely bolted in (almost... see below), I was able to remove the Magnificent Tower of Engine Support that I built:

Next task was to install a little 10mm bolt that goes in from the front of the engine, and holds a bracket for the wiring of the oxygen sensors. It is one of 1000 examples of the way that BMW engineers didn't care if the car could be maintained in the field. The bolt is easily accessible if the exhaust manifold is not yet on the engine, and almost totally inaccessible otherwise. I finally tried my "finger wrench" to at least get the bolt through the bracket:

That worked, and this picture shows just how impossible it is to reach - the bolt is circled:

I tried many things to get it started, and finally came to a sad conclusion: the metal shield between the engine and transmission had slightly shifted, and was blocking the edge of the hole just enough that the bolt could not start on the threads. Fixing that would require putting the trans back on the jack, removing the transmission cross brace and loosening every bolt. Since the hole went all the way through, instead I used a long machine screw with locking hardware to secure the bracket. A workmanlike, permanent solution, but it still felt like cheating. Next time I have the trans out (cue the above-named friends, shouting in dismay) I'll get it all right. The rule I violated: start every bolt before tightening any of them fully!

I had left myself a little reminder about putting gear oil back in the trans, and I did that:

Then the newly painted X-brace went on, and I was about ready for John to come over. No pictures really - it was a straightforward reassembly of some stuff that was too heavy and/or unwieldy for one person to install: the driveshaft and the exhaust system.

In addition, we installed the heat shielding that protects the passenger compartment from exhaust heat. There was one piece that was damaged when I bought the car. Jack Miller identified it as something that needed to be replaced on my very first visit to him. Nice, shiny and $33 from BMW for a bent piece of aluminum foil... grumble...

Then we started the car on the lift - it fired right away, which was gratifying after a couple of months offline. I tested the trans, and all seemed well. The wheels went on, and I went off for a test drive with John following in "Howard", his Escort station wagon. Howard is the winter beater, but it's a pretty good car!  

But as I led John back to his house, a problem was evident: if I was in 2nd or 4th gear and hit a bump, the car popped out of gear. Oh no... I chatted with John about it for a minute, and then continued my test drive. I wanted to drive the car for about an hour after its long nap.

As I drove, I reviewed the problem. It was clearly a linkage problem, since it affected the two gears at the bottom of the shift pattern. But there are no adjustments on that linkage, and I had just replace every soft part in the linkage. Then I thought of something else... the big foam sound-deadener that fits around the shift lever. Since I could get to that from above without tools, I pulled over and removed the shift knob, shift boot and the foam pad. That was it! The trans shifted perfectly thereafter, and I couldn't make it pop out of gear no matter how hard I tried.

I reinstalled the pad, and all remained well. I must have had it in crooked the first time. Here it is, in place:

So after all that, I just enjoyed driving the car for a while. I returned to the park where I took the first picture of the 2005 Z4 recently - note that there's no snow on the ground now!

So, the successful end of a long project. I am really thrilled with the outcome - the transmission shifts perfectly, with no slop, a great 2nd-to-3rd speed shift, and a slick, easy action. Now my only decision is what to do with the shirt I've worn all the way through the process - do I try to wash it, or just burn it?