Advice Needed: Problems with GM's 6L45 6AT transmission in my 2011 328i X-Drive

E90SRB · 09-09-2023, 12:44 PM

Hoping the members here might be able to shed some insight.

Car is a 2011 328i X-Drive that had it’s fluid, filter and pan gasket replaced at 144,000km. Last week (the day it hit 150,000km) out of the blue I tap the gas at a green light and it feels as if the transmission and engine are completely disconnected. Car will rev up until practically red line before it shifts violently (feels as if someone is bumping you from behind).

I managined to limp the car home and got code readings:

0056C5 - Electronic Transmission Control, shift valve B, stuck in office position
0056BF - Electronic Transmission Control, clutch, gears 1, 2, 3 and 4, neutral test

I done some pretty extensive research and found individuals who had luck with the Sonnax zip kit + a Sonnax pressure switch rebuild kit to refresh all the parts, while some others go to the other extreme of replacing the entire valve body or transmission.

The transmission shop I towed the car to is probably one of the best in town so I’m inclined to trust their opinion, but they’re quoting me between $3900 and $4500 (CAD) for a “refresh” which could include a new valve, but also new parts within the transmission itself.

Looking at carpart I see there are used transmissions for my car around $900 (CAD) but then again that worries me a little bit because those cars have been in accidents and I don’t know the history of them at all.

Anyone who’s had this issue or experience with this issue that can chime in here? If it’s a $150 part I’d like to skip replacing or refreshing an entire transmission. Originally I was told it was the valve body itself, but from what I’m hearing here these valve bodies don’t really have issues. I’ve seen some people point to the $20 shift selector as potential culprit but all those issues seem to be with putting the car into drive itself.

POBEP · 09-09-2023, 11:30 PM

financially, $900 used one makes more sense.
for $4,000 I would do 3pedal/6MT swap and enjoy a much better car

E92_William · 09-15-2023, 08:19 AM

I would get a used low mileage valve body and you should be perfectly fine after that. While you’re in there put new seals in it and the transmission. No need to do clutches and all that which the shop would probably do for that price

09-09-2023, 12:44 PM	#1
E90SRB New Member 10 Rep 20 Posts Drives: E90 328i X-Drive Join Date: Jun 2019 Location: Canada iTrader: (0)	Advice Needed: Problems with GM's 6L45 6AT transmission in my 2011 328i X-Drive Hoping the members here might be able to shed some insight. Car is a 2011 328i X-Drive that had it’s fluid, filter and pan gasket replaced at 144,000km. Last week (the day it hit 150,000km) out of the blue I tap the gas at a green light and it feels as if the transmission and engine are completely disconnected. Car will rev up until practically red line before it shifts violently (feels as if someone is bumping you from behind). I managined to limp the car home and got code readings: 0056C5 - Electronic Transmission Control, shift valve B, stuck in office position 0056BF - Electronic Transmission Control, clutch, gears 1, 2, 3 and 4, neutral test I done some pretty extensive research and found individuals who had luck with the Sonnax zip kit + a Sonnax pressure switch rebuild kit to refresh all the parts, while some others go to the other extreme of replacing the entire valve body or transmission. The transmission shop I towed the car to is probably one of the best in town so I’m inclined to trust their opinion, but they’re quoting me between $3900 and $4500 (CAD) for a “refresh” which could include a new valve, but also new parts within the transmission itself. Looking at carpart I see there are used transmissions for my car around $900 (CAD) but then again that worries me a little bit because those cars have been in accidents and I don’t know the history of them at all. Anyone who’s had this issue or experience with this issue that can chime in here? If it’s a $150 part I’d like to skip replacing or refreshing an entire transmission. Originally I was told it was the valve body itself, but from what I’m hearing here these valve bodies don’t really have issues. I’ve seen some people point to the $20 shift selector as potential culprit but all those issues seem to be with putting the car into drive itself.
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09-09-2023, 11:30 PM	#2
POBEP Lieutenant 366 Rep 553 Posts Drives: E70 E90 E91 Join Date: Mar 2016 Location: Christmas Valley, CA iTrader: (0) Garage List 2011 E90 335d [9.33] 2013 E70 xDrive35d [5.00] 2009 E91 328i [10.00] 2016 F25 xDrive28d [0.00]	financially, $900 used one makes more sense. for $4,000 I would do 3pedal/6MT swap and enjoy a much better car __________________
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09-15-2023, 08:19 AM	#3
E92_William Captain 1306 Rep 852 Posts Drives: 2008 BMW 328xi Join Date: Apr 2021 Location: South Florida iTrader: (0)	I would get a used low mileage valve body and you should be perfectly fine after that. While you’re in there put new seals in it and the transmission. No need to do clutches and all that which the shop would probably do for that price __________________ Airplane Mechanic BMW Masochist
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