[mousefarmer]

I have previously changed the automatic transmission fluid on the BMW GA6L45R GM transmission maybe 30,000 miles or so ago. It now has about 125,000 miles and is due for another fluid change.

This time I plan on changing out the transmission valve body sleeves, sealing sleeve, gear selector valve after taking out the valve body. I have previously done this on another BMW with the ZF transmission so I think the process is similar.

However, I have never taken fluid out of the torque converter with the valve body removed. I watched this video where he shoved a rod or something and some fluid started coming out:

I previously just would drain fluid, add some fluid, drive around for a while then on next time would remove the transmission pan, put on new filter, replace pan and add the last drain and fill of fluid.

Has anyone tried to remove transmission fluid like shown in the video? Is it risky? I would think if you don't have the right size hose or pressure from fluid pump maybe it would be difficult getting fluid back in the torque converter?

Also, I have no idea about how to set GM transmission adaptions or if it is even possible. Anyone?

parts shown:
https://www.realoem.com/bmw/enUS/sho...diagId=24_1105

[mainbearing]

The pressure switches should be rebuilt in that transmission. See my notes here:
https://www.e90post.com/forums/showp...6&postcount=12

For the valve body and case sleeve seals, you can use GM ones.

I'm not sure if 2011 LCI benefits from a Sonnax ZipKit, but I put one in too (excluding ATF pump area parts which would require transmission removal) and it worked great for pre-LCI 07. The ZipKit comes with imidized check balls, much longer lasting than the factory junk. You can get just the imidized balls without the ZipKit, check on the Sonnax site. The Sonnax ZipKit page also has instructions on valve body disassembly and reassembly.

ACDelco GM Original Equipment 24238925 Automatic Transmission Control Valve Solenoid Filter Plate Kit. This was what I used. The case sleeve itself is reused, with the 3 o-rings/square seal replaced.

https://www.e90post.com/forums/showp...4&postcount=21

I would not bother using compressed air on there to empty the torque converter as in the video. Compressed air is loaded with moisture, it is not good for the transmission. If you have access to compressed nitrogen then go ahead I guess. Or you can do two drains and refills before you drop the pan. By the third fill it should be pretty clean anyway.

I did not "reset" the adaptation. There was a general reset in INPA, but I do not think it included the transmission. Anyway, the transmission will adjust quickly anyway. At least after my valve body work.

Pressure switches are high failure parts. The flimsy discs are not durable and cut themselves out. For rebuilding, Sonnax no longer sells one set of plastic discs (they come in 10 sets), and the tool is sold separately. You may be able to find old stock single set discs and tool out there.

[mousefarmer]

Thanks for the detailed post Mainbearing!

That AC Delco sleeve kit is significantly cheaper than the BMW branded one at FCP Euro, around $25 vs around $105 plus you have to buy an additional trans sealing sleeve for an additional $25.

https://www.amazon.com/ACDelco-24238.../dp/B004JBI64S It does show that there is a newer version of this part number from AC Delco but I'm not sure what has changed

I did find the Sonnax pressure rebuild switch for about $5 at Rock auto that includes five. https://shorturl.at/uwLU8 as well as the kit with tools for $25 there also.

The plastic balls are also very reasonable.

The main thing I noticed is that when I was pulling the car into a parking space with my foot on the brake I felt the car sort of jump forward like it was trying to jump into second gear from first. I think this is what you mean from the 1-2 slip bump, right? From my understanding this is the #4 pressure switch that controls this.

[mainbearing]

I am not sure about a newer version of GM seals, maybe it was the 6L80-90 version? Nice find on the Sonnax single disc set.

I would suggest a Zip Kit, if not already done, the GM seal kit, and the Sonnax pressure switch rebuild kit. As for the manual shift valve, you can use a BMW shift valve, or the aluminum billet Sonnax valve. I used the Sonnax. If you install a Zip Kit then the valve body "separator plate" may need to be changed. I read one member with the latest version just reused. Follow the Sonnax instructions.

To drop the valve body GM used stupid Torx-Plus bolts, I picked up a special socket to avoid rounding off the bolts, although if careful you can use a standard 6-pt socket. Sonnax instruction has all that info. I did not do the pressure switch the first time, but based on reading a mention of them by e90yyc, I went back in again. Yes I dropped the thing twice. LOL. Should have just changed them altogether.

Here is the forum 6L45 Zip Kit thread:
https://www.e90post.com/forums/showthread.php?t=1494501

The Zip Kit solved the common 2-1 downshift kick, which sometimes felt like the car got rear ended. The pressure switches fixed the upshift 1-2, 2-3 and 3-4, which were rough and at the wrong time. I guess because the computer could not tell when the switches flipped.

Here is the GM seal kit I used. GM offers two different heights of center support tubes, possibly explaining the different part number you saw. The 6L45 uses the TALLER support tubes on the left, in the diagram below. Each seal kit will have only one type of center support tubes, therefore order the 6L45-50 kit and not the 6L80-90 kit.

[M-technik-3]

Going to redo mine in June. Thanks for great info here.