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  1. #1
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    Aug 2018
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    1 out of 1 members liked this post. Yes Reputation No

    6AT: Adaptation values before & after some preventative maintenance (and why it's a good idea)!

    Hi guys,

    I thought i'd post why any type of preventative maintenance is good and especially on the ZF 6HP before any form of tuning is applied.
    I decided to check my adaptation values before and after i'd do some service to my trans.
    The stuff i wanted to do for quite some time:

    - Mechatronic adapter seal (figure 8 seal, common failure)
    - 4 mechatronic tube seals
    - Shift solenoids (M-shift)
    - Foam solenoid strip (while i'm at it)
    - Mechatronic sleeve (electronic connector)
    - Oil pan with filter
    - Fresh ZF Lifeguard 6 fluid

    The reason i wanted to do this, is because i think preventative work generally prevents a lot of headache down the road.
    I have my 135i for almost 2 years now and i'm planning to keep it some time.
    When i bought the car and installed MHD and xHP pretty quickly afterwards, i did some maintenance (just a trans fluid refresh).
    From that moment i kept track of my adaptation values (since xHP allows it).
    After driving for a little 2 years (from 68k to 88k miles in that time) and using it as my DD'er and also driving it hard occasionally, my values were:

    Click here to enlarge

    As you can see, they're pretty much 'in spec', since the TCU can compensate up to 750 mbar.
    My shifts weren't rough or jerky in any way, but i think keeping track of the values is good way to see problems coming.
    Now the A and E clutch tend to have higher values, since they're used most of the time:

    A clutch: 1st, 2nd, 3rd and 4th gear
    B clutch: 3rd and 5th gear (and Reverse)
    C clutch: 2nd and 6th gear
    D clutch: 1st gear (and Park, Reverse and Neutral)
    E clutch: 4th, 5th and 6th gear

    Having ALL values higher than normal typically indicates a worn seal or some small pressure loss.
    Having the clutches A and E pass 400 mbar had me planning this job in.
    After replacement of all these parts and doing ZF's tedious relearn procedure (and also driving for approximately 2 weeks to let the adaptations really settle in):

    Click here to enlarge

    Now in D-mode, the trans is pretty much as smooth as before, no big differences here.
    I had a shift flare from 5th to 6th and that's gone.
    On cold engine, i had a somewhat jerkier shift from 3rd to 4th, that's gone.
    My shifts on M-mode have become alot smoother.

    Now what does this tell us?
    Even though i had no issues or codes and i could've probably kept driving like this for a long time, it was a pretty wise decision to do this.
    Especially for people running much higher torque than stock, this is a good idea :-)
    Keep in mind, most people drive their 6AT BMW and don't keep track of these values.
    When one of the clutches max out at 750 mbar (a pressure loss due to the worn seal accelerates this proces obviously), the TCU can't compensate further and you will run into slipping issues.
    If you keep driving like this for extended time (and probably higher torque than stock), you can really fry your clutches fairly quick.

    Keep your 6AT happy and it will keep you happy :-)

  2. #2
    Join Date
    Dec 2019
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    2 out of 2 members liked this post. Yes Reputation No
    This is good outcome, although XHP suggest against resetting adaptations unless after a repair/rebuild.

    Are you still checking your adaptations value and they are pretty much stable and not increasing again?

    Also any tips on where to source the service parts specially the solenoids?
    My clutch A is showing over 500 mbar ATM. The rest are not too bad.

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