Need opinion from G/B experts

[rpmnut]

Hey guys,I've been getting mixed signals from BMW "specialists" out there. Been thinking of servicing the valve body on my E39 gearbox (ZF5HP19). I've done a gearbox reset and a software update as well as changing the gearbox mountings, but after a week of smooth running, the gearbox is back to having a slightly jerky 3rd to 2nd downshift. No other gears are affected. Upshifts through the gears are silky smooth. Downshifts from 5-4-3 is also smooth, but when it shifts from 3-2 at slow speeds on level ground, there's a noticeable jerk from the driveline. Weirdly enough, if I slow down on a decline or incline, there's no jerk.I consulted AB (a friend works in the service dept) who did an OBD check and found no error codes. But he said that I might need to service the valve body on the ZF as he suspects there's a sticking solenoid. Apparently this would't show as an error code on the E39's diagnostics. So replacement of the affected solenoid should solve the problem.Then when I sent the car to Ah Wai for a routine bulb replacement and asked him about what AB had told me, he said servicing the valve body can be done, but it normally doesn't do much as once the g/b starts acting up it's a sign it's time for replacement.So my question to all the ZF sifus out there.....should I spend 1k+ to service and replace the solenoids or do you reckon I really need a new gearbox? Many thanks in advance for your input:wink:

 

[Herbert]

Two things could be defective:-

1. auto clutch plates 2 & 3 worn off and/or
2. one of the solenoids in the valve body is defective

Logically you should service the valve body first before attempting to overhaul/replace your gearbox.

 

[rpmnut]

Any idea what kinda prices I should be paying for the service & solenoid replacement, Herbert?

 

[EtEE]

Aiks, I'm experiencing a similar prob like yours. There's a jerk when down shift around 1,500 to 2,000 rpm. But I'm not sure from which gear, probably 3rd to 2nd. The rpm rev up slightly when this happen.

I have change the gb sensor harness. Problem still hanging around. Btw, mine's an e46325i msport. Hope there's a solution b4 things get worse

 

[bimmerholic]

rpmnut....any updates on your GB so far?

 

[rpmnut]

Yup. My 525i was diagnosed with a faulty torque converter.
Had the gearbox removed, converter replaced, and now the car is running smoothly again

 

[Vincent Hor]

Bro, please share with us the workshop that solved the problem.

 

[rpmnut]

M Motor Garage at Bandar Tun Razak.
Took a few tries to diagnose the issue, but I'm thankful they didn't just guess & try to fix the problem by replacing expensive parts.

 

[bimmerholic]

Yup. My 525i was diagnosed with a faulty torque converter.
Had the gearbox removed, converter replaced, and now the car is running smoothly again

Did an error popped out this time pointing to the T.C (torque converter)? What's the damage like bro?

On contrary to the T.C, do you think that the problem could have been solved if you just replace your ATF instead? Reason being is, when the T.C was removed, you still had to replace the ATF.

 

[rpmnut]

Hey bimmerholic - there were no error messages on the OBD relating to the gearbox. That was what baffled the BMW guys in the first place. They scanned the ECU and not a single error code appeared. But something was obviously still not right.

My guess is that not all machanical problems can be traced using error codes. My own suspicion is the lock up clutch in the g/b. I read on the BMW USA forums that the lock up clutch can sometimes start to have problems in engaging/disengaging. If the clutch doesn't engage at all, an error message will appear. But what I felt was happening here was that the lock up clutch was disengaging late, causing the jerk - but because it actually did disengage, no error messages appeared. I could be wrong though...LOL. This is me playing witch doctor lah!

As for th eATF fluid, I flushed and replaced my ATF, filters..etc when the problem first started, hoping that it would solve the issue, but even after that job, the gearbox was still jerking on downshift.