[nazb]

Hi there,

I own a 330i Auto with the ZF 6HP19 gearbox. Car's done 82500 miles.

For a while now, when I drive on the motorway or any faster road where there are the typical undulations/small bumps, my gearbox would slip out of gear and then slip back into the desired gear. I knew it wasn't normal behaviour, but since the car kept driving I didn't think much of it.

As a precaution, I did an in-depth gearbox service;

• Mechatronic Sleeves
• Bridge connector
• Plug adapter seal
• Fresh ZF Lifeguard 6 fluid
• Transmission oil pan (filter built in of course)

I thought this would solve my issue with bumps, but it persisted and didn't go away. I figured it was normal behaviour. I don't really have any other experience with these transmissions as this is my first BMW and I've learned as much as I can to DIY most of the work (only thing I didn't have the facilities for was replacing the rear subframe). Nonetheless, the gearbox shifted much smoother aside from that issue.

One day however, I was driving to Luton on the M1, and as I drove over the typical motorway bumps the yellow cog of death appeared. It wouldn't shift out of gear (I think third maybe). I pulled into the nearest petrol station and restarted the car (key out/in) and the error went away. I own a code reader and saw some of the stored codes were tagged as 'History' rather than 'Current' so I thought it was just a glitch.

As I was returning home on the M1, again I drove over the typical undulation in the road but this time it felt much different, the gear selector was vibrating and the HUD showing what gear you're in was flashing like it didn't know what to do.

I've asked BMW Doctor Dean about this and he mentioned that my DME may potentially be water damaged and that the jolts in the road are causing my issues as the water sloshes around the DME box. I'm going to check my wiring over the weekend to verify if that's the case.

My only thought on that opinion is that, why didn't it happen when I was driving over pot holes for example, or speed bumps? Wouldn't that cause the water to slosh around as well?

I also understand that the side drains (not sure what the official term for them is; the ones with the leaf catcher mesh thing?) get clogged with leaves and other debris, but I always clean the leaves out of it and the drains aren't clogged. So not sure what could have gone wrong since it gets rained on and washed regularly and never had an issue until now.

I also noticed that if I go over those harsh (yellow and black plastic) bumps at supermarket car parks at a normal speed the engine would just stop. No error codes whatsoever. Just needed to press the start button and all would be normal again. I never go over those humps quickly, always slowly so I've not seen any issues there.

The issue seems to always stem from going over certain kinds of bumps.

Currently, the engine starts just fine and the errors on the dash have gone away. Gearbox selects PRND/DS just fine and the errors on my code reader show that the transmission related faults are in history.

If anyone has experienced this issue before or could provide any insight, I would be eternally grateful .

I've attached images of my error codes from my Launch CReader Elite. The DSC errors can be ignored as those bits have already been rectified. I've not cleared them as one of the transmission faults is part of that module as well, probably cruise control related.

Update: I forgot to add codes from another module.

Thanks,
Naz