ZF6HP19 Auto Issues (Slamming)

ZF6HP19 Auto Issues (Slamming)

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nipsips

Original Poster:

1,166 posts

142 months

Saturday 22nd April 2023
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Hi guys,

I've got an issue with my BMW E90 325i fitted with a ZF6HP19 gearbox. This gearbox appears to have been fitted in Ford's, Audi's, BMW's, Landrovers/Jaguars etc - its a really common box but I've got a weird fault.

Basically the gearbox has started slamming - both sometimes while stationary and driving.

It started off:

1) Downshifting affecting all gears when going downhill was intermittently hard pointing to solenoids, gear shift indicator would disappear from instrument cluster
2) When stationary in D gearbox would slam and feel like it was trying to engage 6th, gear shift indicator would disappear from instrument cluster
3) When driving in D gearbox would slip while the gear shift indicator had disappeared from cluster, and then slam when D reappeared. If driven in manual mode as soon as it slips and slams would reset itself to DS mode (default mode while selector is in this position).
4) When stationary in P or N gear shift indicator disappears from instrument cluster and then reappears and engine revs pulse.

There are no fault codes within the car relating to this - only relating to the stereo and MOST config as I've got a iPod adaptor connected and a faulty heater blend motor.

When INPA is connected to the EGS (gearbox module) I can see an EGS reset on the info screen every time it does this for an extended period however when the gear shift indicator disappears the EGS disables from INPA so I cant see any live data but when its connected and working I can see solenoids working fine and the L1-4 switch (the bit that tells the mechatronics to be in P/R/N/D) appears to be OK -however the fact its appears to be losing comms should be noted via the DME (ECU) and by the junction box module that controls the powertrain canbus. I've got the following theory's:

1) Mechatronics sleeve adaptor is leaking and playing havoc internally in the connector, gearbox module gets confused, resets and slams it between neutral and reverse too quickly for the solenoid to retract so it slams. I do have a slight weep from this adaptor as it wasn't changed when the fluid was done last year. No fault codes as when it comes back online it thinks its ok so the car doesn't report it as its literally a split second.
2) Gearbox groundings appeared to be shared with the engine loom - earth strap somewhere is playing up or there's an intermittent short in one of the wiring harnesses.
3) EGS has fried and requires replacement - built into mechatronics unit along with solenoid valves. Unless a solenoid is shorting and resetting the EGS I cant see how it can be a solenoid.

Worth mentioning the car had a recent battery, alternator appears to be kicking out the correct voltage and when the info resets are happening the EGS is receiving between 12-14 volts so no issues there.

Does anyone have any other things that I could check before I start spending mega money? smile

Thank you kindly.

gweaver

911 posts

165 months

Saturday 29th April 2023
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Have you had the ATF changed?

nipsips

Original Poster:

1,166 posts

142 months

Saturday 29th April 2023
quotequote all
Hiya,

Yes I have! Issue seems to have been solved by retightening the coil pack earth bolt on the engine block would you believe.

Took a while to figure it out but it’s sorted now smile

Thank you!

gweaver

911 posts

165 months

Sunday 30th April 2023
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Sorry, just saw you'd mentioned having the fluid done - I'd missed that. Good that the box is behaving now.

We've got an old Vauxhall that occasionally slams up the gears, either going up hills or under hard acceleration. We had the box serviced around eighteen months ago, so the fluid is relatively fresh. I'll check what was done when the box was serviced, but if cleaning up some connectors and earthing points worked that'd be great.

nipsips

Original Poster:

1,166 posts

142 months

Sunday 30th April 2023
quotequote all
Tbh it’s the first thing with an auto box I do nowadays anyway, although manufacturers are still insistent on not changing the fluid. I’ve got a 2019 308 fitted with an Aisin Warner auto box and apparently that’s sealed for life. It’s done 100k now so we shall see how that deals with old fluid.

I think I got lucky, if it’s anything like the ZF6 box’s they use solenoids and the solenoids wear eventually hence the hard shift.

I’m not an expert but I’d certainly trawl forums before stripping anything out - luckily the ZF6 is fitted to so many cars there’s a wealth of information out there on them.