[Snowy_e91]

Originally Posted by Snowy_e91

Thanks for your reply.

My understanding, after doing some digging, is that it's possible with the GM transmission for the check valve which sits between the valve body plates to become worn, causing it to dislodge itself and become stuck between the plates.

My hope is that with a full valve body rebuild, this, along with solenoids would be taken care of.

It also seems as though a software reset and update would be advisable....

So the valve body specialist determined that the valve body (and its contents) work perfectly. It is their diagnosis that clutch pack B has failed.

This leaves me with a car that is otherwise excellent but in need of a new transmission...

Thanks for everyone who responded!

[LanDzia]

Get a second opinion. I'm not saying it's not true, but sounds too convenient coming from a place that prefer to offer a full rebuild.

[lordnikon]

Originally Posted by LanDzia

Get a second opinion. I'm notnl saying it's true, but sounds too convenient coming from a place that prefer to offer a full rebuild.

x2

[Snowy_e91]

Originally Posted by lordnikon

x2

Completely agree.

Just wondering now that the car isn't drivable if I should have it towed to transmission specialists or another independent BMW mechanic.

[LanDzia]

Originally Posted by Snowy_e91

Completely agree.

Just wondering now that the car isn't drivable if I should have it towed to transmission specialists or another independent BMW mechanic.

I'm of course not an expert, but 56C5 Shift valve B: stuck in off position sounds exactly like solenoid got stuck.

If its indeed ZF, then it's very common for sleeves and solenoids fail, even though car won't throw even any code, ir even they might look OK.
I've heard more times than not - failing valve body is responsible for 95% of transmission issues.
That being said, if you keep driving and getting error, you will destroy your clutches.

Also interesting if there was any metal shavings on pan when dropping before. That would be a good indication.

After all, even if you rebuild valve body with solenoids and its still the problem, you can keep it and just rebuild transmission with clutches.

[Snowy_e91]

Originally Posted by LanDzia

I'm of course not an expert, but 56C5 Shift valve B: stuck in off position sounds exactly like solenoid got stuck.

If its indeed ZF, then it's very common for sleeves and solenoids fail, even though car won't throw even any code, ir even they might look OK.
I've heard more times than not - failing valve body is responsible for 95% of transmission issues.
That being said, if you keep driving and getting error, you will destroy your clutches.

Also interesting if there was any metal shavings on pan when dropping before. That would be a good indication.

After all, even if you rebuild valve body with solenoids and its still the problem, you can keep it and just rebuild transmission with clutches.

It is the GM, but it does seem like the valve body (and therefore solenoids) are fine. This to my knowledge leaves only internal parts.

Quotes to rebuild the transmission vary wildly, too.

[lordnikon]

Originally Posted by Snowy_e91

It is the GM, but it does seem like the valve body (and therefore solenoids) are fine. This to my knowledge leaves only internal parts.

Quotes to rebuild the transmission vary wildly, too.

The GM transmission does not use solenoids. It has checkballs instead.

[Snowy_e91]

Originally Posted by lordnikon

The GM transmission does not use solenoids. It has checkballs instead.

Yes, thanks for the correction. I believe that the balls can occasionally fail and become dislodged. I assume that the valve body specialist would have seen this in their testing...

[Snowy_e91]

I should also just put this out there:

Apart from what has been done - fluid and filter, neutral safety switch, test the valve body, replace sleeves - its there anything I'm missing that isn't internal?

[gbalthrop]

Originally Posted by Snowy_e91

... Just wondering now that the car isn't drivable if I should have it towed to transmission specialists or another independent BMW mechanic.

Questions/ Comments/ Rant:
1) Has any "diagnosis" to date been done by an "Indy"?
2) does that "Indy" do Transmission Rebuild?
3) Who did any "Transmission Work" that was done shortly before Codes, Limp Mode & improper shift operation?
4) Who initially told you the transmission pan was Plastic & you had ZF AT on E91 328i?
5) In Post #17, you stated that you had just learned your AT is GM6. That GM6 uses Different: Pan, Filter, & FLUID than ZF.
6) Shops are in business to make money; overseeing/ training new employees takes time & reduces Revenue$. Today's business model: OVER-Sell your skills: e.g. "I alone can fix it"; "I know all the Best People". ALSO: Push each job DOWN to Lowest-Paid person who MAY (MAY NOT) have required skills/knowledge to perform. If your "Customer/ Mark" does NOT have knowledge of HOW his car works: Over-Charge/ B$. EVERYONE makes mistakes -- some even on a GOOD Day.

Bottom-Line: Yes, I AM CYNICAL.

I would call several "Automatic Transmission Shops", ask to speak to the Manager, & ask Him if shop has done DIAGNOSIS & Repair of GM6 (GA6L45R) transmission. ALSO ask if shop: (1) has software/ Scan Tool to read "Live data" in the GS1912 Transmission Control Module, & (2) HOW would he diagnose: 56C5, "Shift valve B: stuck in off position".

If THAT does NOT instill confidence that YOU have found a trustworthy/ capable shop, I would call several BMW dealers & ask WHO they use for transmission repair/ diagnosis. I have done ALL my own work on my vehicles for 60+ years, EXCEPT Automatic Transmission repair/ rebuild. It takes a shop with specialized Equipment & Knowledge to properly diagnose & repair AT issues. There are even ways a good DIY'er can screw up a GM6 Fluid & Filter change, but it's relatively simple if you take your time & READ.

ASK shop to check fluid Level & Type. Ask if any type of pressure Gauge can be attached to TEST. Ask if they have INPA or equivalent Software to DIAGNOSE your issue. Ask if they REBUILD that transmission, or only R&R (Remove & Replace). Ask CO$T of each option.

ASK: If car can be driven in 3rd gear (Limp Mode), & is that going to harm anything as long as YOU are safe Driving it to shop?

TOW ONCE ONLY. Please let us know what you find.
George

[Snowy_e91]

Originally Posted by gbalthrop

Questions/ Comments/ Rant:
1) Has any "diagnosis" to date been done by an "Indy"?
2) does that "Indy" do Transmission Rebuild?
3) Who did any "Transmission Work" that was done shortly before Codes, Limp Mode & improper shift operation?
4) Who initially told you the transmission pan was Plastic & you had ZF AT on E91 328i?
5) In Post #17, you stated that you had just learned your AT is GM6. That GM6 uses Different: Pan, Filter, & FLUID than ZF.
6) Shops are in business to make money; overseeing/ training new employees takes time & reduces Revenue$. Today's business model: OVER-Sell your skills: e.g. "I alone can fix it"; "I know all the Best People". ALSO: Push each job DOWN to Lowest-Paid person who MAY (MAY NOT) have required skills/knowledge to perform. If your "Customer/ Mark" does NOT have knowledge of HOW his car works: Over-Charge/ B$. EVERYONE makes mistakes -- some even on a GOOD Day.

Bottom-Line: Yes, I AM CYNICAL.

I would call several "Automatic Transmission Shops", ask to speak to the Manager, & ask Him if shop has done DIAGNOSIS & Repair of GM6 (GA6L45R) transmission. ALSO ask if shop: (1) has software/ Scan Tool to read "Live data" in the GS1912 Transmission Control Module, & (2) HOW would he diagnose: 56C5, "Shift valve B: stuck in off position".

If THAT does NOT instill confidence that YOU have found a trustworthy/ capable shop, I would call several BMW dealers & ask WHO they use for transmission repair/ diagnosis. I have done ALL my own work on my vehicles for 60+ years, EXCEPT Automatic Transmission repair/ rebuild. It takes a shop with specialized Equipment & Knowledge to properly diagnose & repair AT issues. There are even ways a good DIY'er can screw up a GM6 Fluid & Filter change, but it's relatively simple if you take your time & READ.

ASK shop to check fluid Level & Type. Ask if any type of pressure Gauge can be attached to TEST. Ask if they have INPA or equivalent Software to DIAGNOSE your issue. Ask if they REBUILD that transmission, or only R&R (Remove & Replace). Ask CO$T of each option.

ASK: If car can be driven in 3rd gear (Limp Mode), & is that going to harm anything as long as YOU are safe Driving it to shop?

TOW ONCE ONLY. Please let us know what you find.
George

I appreciate this kind of rant!

I'll most likely have the thing towed to the most reputable transmission specialist within a reasonable distance next week.

The average cost to rebuild in this area is between $6,500 and $7,200, so this is not an ideal scenario to be in.

What I do not like about what I've been told so far (by the Indy BMW mechanic who sent the valve body off) is that the valve body was tested and was fine, but when I asked about check balls etc he had no idea at all, and was unsure about the solenoid situation at all...

I don't mean to say they are dishonest or don't know the mechanical work, but it's all been very vague from the start.

I'm a car enthusiast who understands basic mechanics, but I am no expert. There is just something that doesn't add up about how this has been handled in my opinion.

Of course I am likely wrong, but given that it is unlikely for this transmission to fail internally at this mileage with a good service history (the services were done by a reputable shop) I want to question things before just throwing money at people.