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      03-25-2021, 09:48 PM   #1
ingl0405
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Drives: BMW 650i
Join Date: May 2020
Location: Canada

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Exclamation Random Rough Shifts 1-2 gear ZF8HP

Hi,

I have found a few posts online regarding rough transmission issues pertaining to the ZF8HP transmission, but none of them actually had a real solution posted, so I thought I'd document my issue.

I have a 2012 650i (F12 chasis) with a ZF8HP, I believe Gen 1. Approx 90k kms. I don't drive the car too hard, mostly in comfort and moderately and I am very careful with not abusing it.

The symptoms:
- When trying to drive smoothly (IE trying not to leave everyone behind at the stoplight), the transmission will surge into second gear (around 1500 RPM). It feels like being kicked in the a** and the car lunges forward.
- This seems to happen randomly. There are times when this will happen, and days when it behaves and does not "kick".
- Usually I know it's either going to be a smooth day or a day where the car will decide to kick me for trying to drive smoothly.
- If it's a smooth day, the shifts are barely noticeable.
- If it's a bad day it will kick my a** into 2nd every other time I start slow from a stoplight.
- On one of its bad days, if I drive aggressively, the rough shift can't be felt although I suspect it's still happening.

What I ruled out:
- It's not temperature related. Happens both when engine is cold or warm, though slightly more when warm
- The drive mode (Comfort, Sport, Sport+ has no impact)

What I noticed:
- Seems to happen more often after being stuck in stop and go traffic.
- Less obvious if going uphill, such as a parking ramp.

What I have done so far:
- I had the dealer perform a major service (replace fluid and filter)
- They also reset the driving adaptations. I know the 6HP has a re-learning procedure but I tried to look for one for the 8HP but found none.
- After the reset it was ok for a few days then it started acting up again.

Since I doubt the solution is to punch down on a transmission that may have issues , I would very much like to get to the bottom of this.

If you have experienced similar issues, please let me know, otherwise I will document my experience below.

Thank you
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