330d auto 6HP26 issues

[fz1er]

Morning,

Hoping someone can help.

The car is on 225000 miles (06 plate). I have had it since 90000. I have never done a gearbox service on it so I'm guessing the old owner did.

A month ago the car started to hold its 4th and 5th gear. Shortly after it started to struggle finding 3rd gear.

I brought some oil and a new pan and got it all changed. The oil was black and it looked like the pan had warped slightly. After changing the oil it was fine for 40 miles and now it has gone back to how it was.

Just wondering where to go next. I have had a good look on the internet to find its either the solenoids or the valve body.

Anyone know whether its more likely to be the Solenoids or valve body?

Thanks

[pmorg4]

There's every likelihood that the previous owner hadn't serviced the box (there is no maintenance scheduled by BMW on these), so it probably hasn't been serviced since new.

At that mileage it would have been well worth changing the seals behind the mechatronics unit (bridge seal and four tubes) whilst the pan was off. It doesn't add much to the job and the parts are cheap, which could have improved your problem (or it might have made no difference, impossible to know really). Beyond that, it's hard to say what the problem could be. You could reset adaptations and go through the re-learning procedure as a no-cost initial approach, but it seems likely that there's a hardware issue somewhere.

[fz1er]

Thanks for your reply.

I think its an hardware issue.

I will try the reset to see if it makes a difference. If I cant figure out which one it is I might as well buy a gearbox with warranty.. Just dont know.

[Court_S]

As per PMorg's post were the adaptations reset after the gearbox was serviced?

Its probably worth doing the mechantronic seals and possible the solenoids.

[pmorg4]

If you can do the work yourself and don't mind potentially having to go in there twice, I'd start with the seals as they are cheap. You can re-use your oil and pan, no point in wasting £300 worth of new parts! Or if you'd prefer to just spend the money and do the lot in one go, change the solenoids too.

A used box is an option but if it was me going to all the expense and effort I'd be changing the oil, pan and seals on the used box anyway whilst the box is off the car, so no harm trying on your existing box first to see if that fixes the problem, and if not you can swap the new parts onto the used box.

[helix402]

That’s the sort of mileage these boxes fail at sadly.

[fz1er]

Thanks all,

I did an adaptions reset and it's made it worse

Think I will take your advice and do the seals and solenoids. Thinking about it the new box might have the same issue so might as well keep this one going.

It's fine in manual.

[pmorg4]

There is a specific re-learning procedure to follow after the reset (search around, it's on loads of sites), so make sure you try that to see if it improves.

If it's shifting perfectly in manual mode that suggests that there's no issue with the gearbox hardware, which is surprising.

[fz1er]

Just found it. I will give it a go.

[I-am-the-reverend]

fz1er said:

Thanks all,

I did an adaptions reset and it's made it worse

Think I will take your advice and do the seals and solenoids. Thinking about it the new box might have the same issue so might as well keep this one going.

It's fine in manual.

Don't rule out an ABS/DSC fault. I recall an absolute bd of an E46 with a similar fault. Nothing would fix it - it even had a known good used box fitted.

In the end it was found that the ABS ECU on the pump was faulty and even though there were no fault codes, a used ABS unit fixed it. The fault was found purely by accident when a rear sensor failed. With the ABS death light on, the gearbox behaved. Fitted a new sensor and it was back to its old tricks.

It might be worth scanning for ABS faults or unplugging a sensor and seeing if it changes anything.

[fz1er]

I-am-the-reverend said:

fz1er said:

Thanks all,

I did an adaptions reset and it's made it worse

Think I will take your advice and do the seals and solenoids. Thinking about it the new box might have the same issue so might as well keep this one going.

It's fine in manual.

Don't rule out an ABS/DSC fault. I recall an absolute bd of an E46 with a similar fault. Nothing would fix it - it even had a known good used box fitted.

In the end it was found that the ABS ECU on the pump was faulty and even though there were no fault codes, a used ABS unit fixed it. The fault was found purely by accident when a rear sensor failed. With the ABS death light on, the gearbox behaved. Fitted a new sensor and it was back to its old tricks.

It might be worth scanning for ABS faults or unplugging a sensor and seeing if it changes anything.

This is interesting. When the gearbox started playing up I had a bearing fail on the back. It was that bad it took out my wheel speed sensor.. The only reason I knew I had a bad bearing was because speed sensor failed.

When I got the car back all warning lights where off.

What was your gearbox doing when you had this issue?

[I-am-the-reverend]

It was a customer car that wouldn't change up into 4th or 5th unless you did it manually.

[nipsips]

When you say after 40 miles it’s the same do you mean the shift pattern or the fluid colour? Have you noticed the gearshift indicator disappearing from the cluster?

I’d be hesitant about changing solenoids/stripping until you’ve checked the following:

1) mechatronics sleeve has no oil contamination in it
2) gearbox solenoids are responding on Inpa/Ista, you’ll see the solenoid activate via the software then feel the gearbox change, if the EGS asks the solenoid to change and you don’t feel it change you know it’s a sticky solenoid or mechatronics issue.
3) does it respond normally to manual shifts? If it does then it’s probably not the solenoids as there’s no difference between the car deciding to change gear or you. At this point I’d be looking at DME faults, or wheel speed sensors as above
4) is the fluid level still ok or do you have a leak?

There are 1001 reasons why these gearboxes mess around, I nearly changed my solenoids until I found a loose earth bolt. Just investigate it properly and you can diagnose it properly

[pmorg4]

nipsips said:

When you say after 40 miles it’s the same do you mean the shift pattern or the fluid colour? Have you noticed the gearshift indicator disappearing from the cluster?

I’d be hesitant about changing solenoids/stripping until you’ve checked the following:

1) mechatronics sleeve has no oil contamination in it
2) gearbox solenoids are responding on Inpa/Ista, you’ll see the solenoid activate via the software then feel the gearbox change, if the EGS asks the solenoid to change and you don’t feel it change you know it’s a sticky solenoid or mechatronics issue.
3) does it respond normally to manual shifts? If it does then it’s probably not the solenoids as there’s no difference between the car deciding to change gear or you. At this point I’d be looking at DME faults, or wheel speed sensors as above
4) is the fluid level still ok or do you have a leak?

There are 1001 reasons why these gearboxes mess around, I nearly changed my solenoids until I found a loose earth bolt. Just investigate it properly and you can diagnose it properly

This is all good advice - diagnose the issue rather than throwing parts/money at it. Having access to INPA/ISTA and knowing how to use it is a huge help in cases like this.

[fz1er]

nipsips said:

When you say after 40 miles it’s the same do you mean the shift pattern or the fluid colour? Have you noticed the gearshift indicator disappearing from the cluster?

I’d be hesitant about changing solenoids/stripping until you’ve checked the following:

1) mechatronics sleeve has no oil contamination in it
2) gearbox solenoids are responding on Inpa/Ista, you’ll see the solenoid activate via the software then feel the gearbox change, if the EGS asks the solenoid to change and you don’t feel it change you know it’s a sticky solenoid or mechatronics issue.
3) does it respond normally to manual shifts? If it does then it’s probably not the solenoids as there’s no difference between the car deciding to change gear or you. At this point I’d be looking at DME faults, or wheel speed sensors as above
4) is the fluid level still ok or do you have a leak?

There are 1001 reasons why these gearboxes mess around, I nearly changed my solenoids until I found a loose earth bolt. Just investigate it properly and you can diagnose it properly

Thanks for this.

I will see if my mechanic has the BMW software.

Took it out today the problems aren't every time. The holding gear seems to be on the slightest of inclines. The struggle between 2nd and 3rd isn't every time.

Also yesterday coming to a stop the whole car vibrated and seemed to lurch forward a little.

In manual I don't get the 2nd to 3rd issue but when I change the dash shows 3rd a second before it changes to 3rd.

None of this happened in the first 40 miles after the oil change but I have since found out the adaptions were reset after.

Thanks to everyone for helping me. It's getting pretty annoying as I can do upto 800 miles in one week sometimes.

[nipsips]

pmorg4 said:

This is all good advice - diagnose the issue rather than throwing parts/money at it. Having access to INPA/ISTA and knowing how to use it is a huge help in cases like this.

Sadly I had a crash course on ZF’s when mine was messing about - if I’d have changed the mechatronics like I was debating I would have been fuming!

[nipsips]

fz1er said:

Thanks for this.

I will see if my mechanic has the BMW software.

Took it out today the problems aren't every time. The holding gear seems to be on the slightest of inclines. The struggle between 2nd and 3rd isn't every time.

Also yesterday coming to a stop the whole car vibrated and seemed to lurch forward a little.

In manual I don't get the 2nd to 3rd issue but when I change the dash shows 3rd a second before it changes to 3rd.

None of this happened in the first 40 miles after the oil change but I have since found out the adaptions were reset after.

Thanks to everyone for helping me. It's getting pretty annoying as I can do upto 800 miles in one week sometimes.

He really needs to have the software to be able to to interrogate what’s actually happening. The EGS (trans module) saves both fault codes that bring the cog onto the dash, and also the info codes that it just reports - when my gearbox was messing about I had lots of EGS reset fault codes.

Normally in my experience other than a sticky solenoid if a fault is intermittent it rules out major things because why would it shift fine occasionally and then not - it sounds either software or loose connection on the loom somewhere.

I can’t stress enough checking the earth strap on the transmission loom, on the petrol engines it’s shared with the ignition coils and goes between the cylinder head and the OSF strut tower but I’m not sure if the diesel will be different.

Also I don’t think there is much to be gained out of resetting the adaptions, it’s not highly recommended unless hardware is changed.

Changing the solenoids is quite a simple job, however I’d begrudge doing it if it didn’t cure my fault and it turned out to be something else after putting all of that work into it.