Took on the ZF tranny pan replacement and fluid change on my 2006 330xi (82083 miles, I just bought it a month ago with just over 81K on it, no signs in Carfax that this had ever been done). The car has the ZF tranny. I had intended to also do the mechatronic sleeve replacement but once I got the old pan off and located the mechatronic connector, I realized this was going to be a LOT more work that likely would involve dropping the exhaust and/or the transfer case. So, I decided NOT to do the sleeve replacement. It's not leaking as far as I can tell, so just hoping it holds up until the next pan/fluid change in 50-60k miles or so and will do it then or have an Indy do the job.
There's several other threads related to changing the pan and/or fluid change. chriztofor and sammy_0559's threads were very helpful even though they were for 'i' models, thanks to both of them for their excellent writeups! I wanted to put my xi experience in its own thread instead of tacking them on somewhere within their 'i' threads.
Some other helpful info can be found here:
Here's what I did:
- Front wheels were on ramps, rear of car was on jackstands
- Unbolted the front driveshaft from the transfer case and let it hang down. If you're using 4 jackstands, you'll be able to just spin the front wheel as necessary to get access to all 4 of the driveshaft bolts. Since I was using ramps on the front, I had to jack up one side of the front to allow me to turn that wheel to rotate the driveshaft.
- Break-loose the tranny fill bolt. As has been posted in many other threads, always make sure to get the fill bolt loose before draining the fluid.
- Opened the plastic drain plug on the tranny and drained the fluid. In my case, the car was up on ramps/stands for 6 days prior and engine had not been on at all during that time, so my pan was nice and full as the torque converter had time to drain a little too. I got about 7 liters out of the tranny (some of that was still in the pan after draining it, but I poured that into the container once I dropped the pan and that's how I got to the 7
- Re-installed the drain plug so that oil isn't dripping on me while unbolting the pan
- Unbolted the pan. Removed all bolts except one in each corner of the pan.
- Removed the remaining 4 bolts while trying to keep the pan pushed up against the tranny. Once all the bolts are out, had to be careful when lowering it, it kinda 'sticks' at the front of the car where the pan filter tube with the gasket on it meets the transmission passage. Don't let the rear tip while getting the tube to come free or there'll be ATF running out the rear of the pan.
- Dumped the rest of the pan into the container with the ATF that was drained via the drain plug. This is how I got to the ~7 liter total.
- Located the mechatronic connector on the back of the tranny; this is where I realized that replacing the mechatronic sleeve was not going to happen.
- Applied thin coat of new ATF to the rubber gasket on the new pan filter tube
- Installed the new pan. It 'thumped' into place when the filter tube seats up into the tranny
- Put a bolt in each corner to hold it in place, then installed the remaining 20 bolts. I put them in barely snug at this point, using just the torx driver installed on a ratchet extension but not using the ratchet.
- Once all the bolts were installed, I then used the ratchet and snugged them again using the pattern specified at thectsc.com site.
- Once I did that, I then restarted from bolt #1 and ran through the tightening pattern again, this time tightening to final tightness.
Each pan through-hole has a metal sleeve in it, so you can't deform the plastic pan by overtightening. However, you CAN snap a bolt by overtightening, which I in-fact did.
I did NOT have a torque wrench that went as low as 10NM, BIG MISTAKE for me because I'm traditionally a slight over-tightener. Luckily the bolt snapped below the surface of the transmission, so I had to take the pan back down and unscrew the broken-off bolt with my fingers and then reinstall the pan and tighten it down. Along with the other parts I ordered, I added 6 new pan bolts to the order because I was worried about something like this happenning. Sure glad I did. Ironically, it was one of the new bolts that snapped! I got SOOOOOOOOO LUCKY with this breaking where it did - if I were cat, I had just used up 8 lives!
- Filled the pan until it started seeping out of the fill hole. I think it took about 3.5 liters to get to this point.
- Installed the fill bolt
- Attached the front driveshaft to the transfer case, 2 bolts was enough (again, there's 4 but you can't do all 4 without spinning a front wheel and to spin the driveshaft to where you can get at the other one or two bolt locations)
- Started the car, WITH FOOT ON BRAKE, cycled through each gear sitting in gear for 3-5 seconds. P, R, N, D, M1, M2, M3, and back, ending in P.
NOTE if using car ramps and not 4 jackstands: I'm not totally certain of this because I don't know exactly what's in the t-case as far as gears, etc., but if the car is NOT in P or N and you take your foot off the brake, I would assume the car will move and this would be a complete disaster. As I said, I used ramps under front wheels, rear was on jack stands, so in my case I would expect the front wheels to pull the car right off the rear jack stands if I took my foot off the brake pedal while in any gear.
From this point forward, the car remained running for the duration of the tranny fill
- Unbolted front driveshaft from the transfer case (leave it mounted to the front differential, it'll rest on a cross-member).
- Opened the fill bolt
- Inserted the thermocouple wire and turn on the meter in temp degrees F mode. I "pre-bent" the wire to point down to hopefully get it to go down in the pan as I pushed it in a few inches.
- Inserted the pump's fill hose
- Re-attached the front driveshaft to the transfer case (again, only used 2 bolts of the 4). The fill tube and thermocouple wire were draped over top of the front driveshaft. I don't know if it would be easy or possible to get those into the fill hole after re-attaching the driveshaft to the t-case, so I put them into the fill hole first.
- Monitored the temperature for specified temperature (86F). I pumped in another 1-2 liters of fluid while waiting here because the temp was not really moving and I thought there probably wasn't enough fluid in the tranny yet to have a pool of oil in the pan for the thermocouple to be soaking in. (Since I got just about 7 liters out when I drained and dropped the old pan and I had added about 3.5 liters to this point, I knew the tranny would take 1-2 liters here and still not be filled to capacity).
- Got in car, WITH FOOT ON BRAKE, cycled through each gear sitting in each gear for 3-5 seconds. P, R, N, D, M1, M2, M3, and back, ending in P.
It took about 20-25 minutes to get to temp. It was pretty cold in the garage and car had not been run for 6 days prior to this. Also, you can hear some what I'll call "strange sounds" from the tranny as it's sitting there in P.
- Once it hit specified temp, pumped fluid in until it seeped out the fill hole.
- Unbolted front driveshaft from t-case
- Installed fill plug into tranny and torque to spec.
Shut off the car at this point.
- Re-attached front driveshaft to t-case and torque to spec
- Old oil was dark, glad I did this
- As I mentioned above, if the front driveshaft is not installed and you shift out of P into a gear, I believe the front driveshaft output mount plate will spin and I didn't want that to happen. So, that's why my process was to always have the driveshaft connected before shifting through the gears. I'm not sure if it'd be OK to have it spinning un-loaded, and the fluid fill hose and thermocouple would be near that area so would have to be careful to not let them get smacked by the spinning mount plate. However, if someone that knows more about how this t-case system works, please let me know. Maybe if the rear driveshaft can't spin then the front can't spin either? I didn't want to find out in real-time.
- When running the engine after the initial fill of the new pan (where I got about 3.5 liters in), I heard some sounds from the transmission that made me very nervous. I believe I could actually hear it trying to suck fluid up that pan tube but I think it had already sucked the bulk of the fluid up there and so it was pulling just spits of fluid and air. I believe I also heard the sound of air pockets, which I believe makes sense since at this point I was obviously low on fluid in the transmission (the 3.5 I put in plus whatever was left in the cooling lines and the torque converter, I think I read somewhere that the capacity of the system is about 9.5 liters).
- When I first started waiting for the fluid temperature to rise, it was not really moving. This furthered my suspicion that there was not enough fluid in the transmission for the thermocouple to be sitting in a pool of fluid in the pan, so I pumped in a liter or two and that helped. At that point, the thermocouple then was measuring and changing, temp was rising and the sounds I was hearing did stop.
- After I was done, I drove the car easy for about 20 miles, no rapid acceleration, just nice and easy letting the tranny shift up and down through all the gears. After that, I started getting on it a little bit more, but still not too much. Everything felt fine, really couldn't tell any difference from before the pan/fluid change. I'm glad I didn't notice anything different, didn't really have any problems before doing this work, this pan/fluid change was intended just to be preventative. Finally, took it out on the highway up to 75 mph, didn't notice any issues.
- I didn't do the mysterious 'adaptation reset', I haven't done much research on that but what I did do on it seemed like the results were inconclusive.
Hope this information helps someone out. I'm just trying to give back to this awesome forum, it has helped me out already tremendously in the very short time I've owned this car.