X5 E70 8hp automatic transmission behaviour

[fiE70]

I have a 2011 X5 40d and got some time to time weird behavior in my 8hp70 automatic transmission. The oils to the transmission has been changed 3000km ago and adaptations were reset on that time. With the earlier oils this behavior was even worse.



When the car is started on cold weather (-0,5 C) the shifting is not optimal but the issues appear while driving speed around of 85km/h. The transmission changes the gear to back and forth from 7 to 8 from time to time. Somehow it feels like that the car thinks that it is not a capable of driving car with so low rpm's with the gear 8 (~1150rpm/min). When the engine gets warmed everything works correctly and smoothly and in exactly same situation the gear keeps on the gear 8.

The heating of transmission in that temperature takes something like a 15km of drive.

Sometimes while driving with cold transmission it feels like it is testing for a gear 8 even while the rpm's show in instrument cluster to the level of driving with 7 (you can feel a minor "push").





Interesting part is that while driving the cruise control the gear keeps on 8 even with the cold temperature of transmission. There's no any particular vibrations appearing while driving in manual mode with gear 8 for a very low rpm's (so it shouln't be the torque converter issue?) when comparing the car's behaviour to high rpm's and gear 6 or 7 at the same speed.



Are there some software updates available for the automatic transmission which could improve this behavior? What could be causing this issue or is it a feature of all of these 8hp transmissions with cold oils?

[Sophisticated Redneck]

Definitely not normal, I would email ZF directly, they respond quickly. When you reset the adaptations, did you do the relearning procedure?

[fiE70]

I tried to drive carefully for the first 300km after reser but I never didn't found a exact procedure description from google. How it should be done?

And to be honest the working behaviour was a bit better after 1000km since adaptation reset. Still not 100% perfect.

[Ohsoslow]

Mine does the exact same thing.. it seems like a software issue to me.. but I’m no expert!

[ard]

Any codes stored in the transmission computer using a BMW-specific code reader?????

[fiE70]

Originally Posted by ard

Any codes stored in the transmission computer using a BMW-specific code reader?????

No, no fault codes at all.

[fiE70]

Any further ideas what to investigate? Could blocked EGR cause this kind of behavior? How about calibration issues with parking brake (if previous owner has changed the parking brake pads but didn't complete the braking in sequence)...?

[B4_685]

Originally Posted by fiE70

Any further ideas what to investigate? Could blocked EGR cause this kind of behavior? How about calibration issues with parking brake (if previous owner has changed the parking brake pads but didn't complete the braking in sequence)...?

I would try a throttle body reset - if it works correctly with the cruise control engaged, could be a calibration issue with throttle position sensor - at least that’s what I would try next...


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[fiE70]

Do you have some recommendation if the automatic transmission adaptations should be reset at the same time again as the throttle body adaptations will be reset?

Does the throttle body reset contain some risks to mess up something?

Btw, does anyone have the instructions for transmission adaptation calibration drive after reset?

[B4_685]

The reason I would reset throttle body adaptations is that it’s an engine function - if it’s not providing good info to the transmission then it could be creating your issue. I’d do it because its relatively easy to do, requiring no tools - just a sequence involving the accelerator pedal and timing. I’m no tech or anything - it’s just somewhere I might start. Personally it sounds like when the ecu is commanding a throttle position in response to the cruise control, it functions correctly under those conditions. Logic then dictates something to do with throttle position as provided by throttle position sensor(s) and/or accelerator pedal position transmitter (or what ever its called in bmw language)


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