TL;DR - came to shop with no reverse, replaced the drum ONLY, now has several codes and goes into limp after trying for 3rd gear. Also replaced a rectangular section sealing ring with silicon because my boss and the customer have less knowledge than money they're willing to spend. Cannot diagnose, need help!
Let me preface by saying that I'm not a BMW owner, I'm a mechanic with recent BMW woes. That being said, We have a 2000 323i with 140k miles here at the shop that has me pulling my hair out at this point. It came in with a complaint of no reverse. We dropped the pan and found pieces of the 'D' drum sitting in oil that looked like it came out of my Cummins. I recommended removing the trans, performing a full overhaul (all new bearings, seals, o-rings, clutch packs, the whole pizza box), and replacing the broken clutch drum. The customer didn't want to spend any money and the boss didn't want to let the job walk away so they settled on replacing just the broken drum and the four o-rings for the pistons that apply the clutches. Transmission came out without issue. After draining, I opened it up on the bench, removed the filter and set it aside to re-use (sigh....:facepalm
. Valve body came off all together, only removed the ~21 larger-head bolts. Removed the two plastic fluid passages (yellow pieces between VB and front pump) intact, as well as the spring-loaded metal piece and spring from the pump. Pulled the pump off and thoroughly cleaned everything as it came out. I swapped all the old parts from the old drum to the new (with new o-rings on the pistons) and started re-assembly. Everything was going fine until I get to the shaft that runs from the 'A' and 'E' clutch up into the torque converter. On this shaft, there are two rectangular section sealing rings, and one o-ring. I noticed that the foremost rectangular section ring (smaller diameter of the two) was torn and misshapen. This ring is only available as part of the master overhaul kit so again I recommend a full rebuild and am denied. Now, I'm not proud of this next part, and if the excuse "I just work here/do what I'm told" wasn't good enough for Göring, then it's probably not good enough for me either, but, we filled the groove with RTV silicone (high temp), and let 'er cure overnight. Now I'm sure many of you are immediately going to default to this being my problem, but hear me out first. Fast forward to trans re-installation, and fluid fill. We filled the trans through the 8mm hex plug on the left rear corner of the trans, just above the oil pan. Added fluid until it dripped out, started engine, shifted through all positions 4 times and then refilled again while running in park. Trans took a total of ~8/9 quarts, which sounds good to me because total capacity is 9.30qts, but you can never really completely empty the torque converter. When we test drive the car, it now has beautiful reverse. When we drive it down the highway, it shifts 1-2 no problem, then bangs HARD when it tries for 3rd (had all forward gears beforehand). CEL and transmission (!) icon come on and it goes into (i think) a limp mode where it seems to be stuck in 4th or 5th gear, max speed of ~15mph, engine revs all the way up, a la badly slipping clutch. Turn the car off and let it sit for ten minutes and everything is fine again...until 3rd gear. We pulled codes, cleared codes, reset adaptations, disconnected battery, all several times. The condition repeats itself every time.
Now...my first thought was the seal that we should've replaced, BUT, the codes suggest an electrical issue:
83 - EGS ECU internal fault (= P1893, P1894, P1895 i think)
59 - Stall monitering (??)
53 - Gear monitering 3, incorrect ratio (P0733?)
54 - Gear monitering 4, incorrect ratio (P0734?)
49 - Gear monitering (??)
Also have two codes in the ECU for an evap leak and a coolant/tstat issue.
Codes were pulled/cleared etc. with a Snap-On Modis. Also, clutch-brake application chart shows that A, B, C, D, low sprag, and G clutches are all used at least once between P, R, N, D-1, and D-2. E clutch does not engage until 4th and 5th gear. F clutch at 3rd, and for 4th and 5th. So maybe my problem has to do with F clutch? Since everything else seems to work until F clutch applies (or tries to). Now I don't have a fluid flow diagram for this tranny, but from everything I do have, it seems that the rectangular section ring that is now a home made silicon o-ring is separate enough from my problem that I should at least look elsewhere first? I guess what I really need to know is what two fluid passages does this sealing ring separate? If anyone has the exploded view handy, the piece in question is '71.020'.
Final notes, we have been searching and reading everything on the internet. This forum and E46fanatics have been extremely helpful, so we decided to post here after trying everything we could think of/was suggested to us. Hopefully somewhere out there is a ZF god that has actually read all of my ramblings and is about to drop some knowledge on me. Here's hoping! Many thanks to all who took the time to read this!! I'll be checking back and updating through the end of this fiasco.
Warning: PDF! ZF5HP19 spare parts catalog URL: