Removing valve body / mechatronic unit from tiptronic transmission

**54A4Avant** · 07-06-2019,01:21 PM

Has anyone attempted this? I need to take the valve body out of my 6HP19A (KHA gearbox code) and all the YouTube videos for 6HP transmissions seem to show BMWs, which have a different system (pull the white release lever and pop the connector adapter out of the side of the transmission casing).

I believe (but would like to verify) that on the C6, the procedure would be to drop the oil pan, remove the filter then unplug the wiring loom from the side of the mechatronic itself (ie, leave the external loom connected to the transmission casing). Then unscrew the torx 40 bolts and drop the valve body/ mechatronic.

would be great if someone who has previously done this can confirm.

**Crasher** · 07-06-2019,05:07 PM

Drop the fluid, remove the pan, take off the filter, remove the plug from A, remove the clip from A, undo the bolts in sequence.

**54A4Avant** · 07-06-2019,05:45 PM

Awesome, thanks Crasher.

Can i I check the meaning of a couple of those steps? “remove the plug from A” This removing the external connector and harness, ie. unplugging the signal from the ECU at the outside of the gearbox?

“remove the clip from A” - can you elaborate on this one please? Where is the clip, what does it look like? Is it on the outside of the gearbox casing or somewhere on the inside? Does the electrical plug which sits in the side of the gearbox casing pop inwards after the clip is released? (I think there are a couple of O rings to be replaced).

The reason I’m taking the valve body off is to renew the rubber seals (rectangular tall one and 4 cylindrical tubes). My car has the rpm fluctuations at 1400rpm in 4th, 5th and 6th (lockup clutch slip) while transmission is cold, so I’m hoping this fixes it and I can avoid replacing torque converter.

**Crasher** · 07-06-2019,11:08 PM

Yes unplug it and remove its pull through retaining clip. Do you have the equipment to refill and set the ATF level? You are asking questions that concern me as to the ability to do what is a complex task that if screwed up could write off the car.

**54A4Avant** · 08-06-2019,09:01 AM

Well I have an oil syringe pump and the ZF document which details the fill procedure. Plus vcds to monitor trans temp of course. Do I need more equipment than that?

The bit I’m least fully clear on is the adaptation drive after deleting stored adaptation values. Do you know if this has to be run completely as written below or are interruptions to deal with traffic, turning the car around to go back down the same road, etc, ok? If you have to run it exactly as written with no interruptions at all then it must require a helluva long road with no traffic in the way!

**Crasher** · 08-06-2019,07:45 PM

I have never been able to get VCDS to do the adaptation so I use ODIS, some people seem to be able to get it to work, it depends if the pop up’s come up with the values and the drop down tables list it.

**54A4Avant** · 09-06-2019,07:49 AM

Thanks Crasher, I will check my vcds and see what it’s offering. I would also like to note down the existing gearbox adaptation values, so I’m trying to research all the necessary channel numbers and how to interpret them. Transmission channels 73-77 are the basic ones I know, but I guess there is more these transmissions can tell us, with a bit of knowledge.

can I check - the mechatronic diagram you posted above is the correct one for KHA gearbox? It’s just the ZF info I had only shows 10 and 13 screw versions of the valve body, but your diagram has 11. Probably your info is more up to date than the below which I had. Thanks

**Crasher** · 09-06-2019,11:19 AM

That is from ELSA using your box code, remind me tomorrow and I will double check. Could you PM me the UK REG or VIN?

**zit501** · 10-06-2019,09:06 AM

Originally Posted by Crasher

I have never been able to get VCDS to do the adaptation so I use ODIS, some people seem to be able to get it to work, it depends if the pop up’s come up with the values and the drop down tables list it.

I've cleared the clutch adaptions on VCDS a few times before. IIRC, in the transmission controller (channel 2), you go to adaptations - 10, go to channel 01, test, save.
That should clear all the values in channels 73-77. The box might have to be above a certain temp to get it to clear, but it does work.

Don't let anyone tell you that you can do it by holding down the pedal and switching on and off the ignition or some other story.

**Crasher** · 10-06-2019,09:22 AM

Originally Posted by zit501

Don't let anyone tell you that you can do it by holding down the pedal and switching on and off the ignition or some other story.

There are lots of old wive's tales like that. Clearing the learnt values isn't the issue, it is the basic settings to speed up the learning process, rather like performing the readiness code on an engine. It will do it itself but it takes a long time.