Transmission or torque converter slipping

[scottgun]

Hi all,

I've got a recently new to me 2012 X5d with 120k miles. This is my first diesel, so I'm unsure if this behavior is normal or what my next steps should be.

I did not notice this behavior during the initial test drive, but it could have been there and I just dont remember it. When accelerating from a stop or low speeds with light throttle, the transmission seems to slip quite a lot, as though the torque converter is not locking up. After 2 or 3 seconds, the torque converter locks up and will accelerate as expected with no slipping between shifts. It's just the initial 2 or 3 seconds, which feels like a lot. It also seems to allow the engine to spin all the way down to idle.

Here is a short video of the behavior.
https://streamable.com/rx2dca

I have tried:

• Replacing fluid and filter (liqui-moly toptec 1800)
• Replacing valve body seals
• Replacing valve body solenoids
• Resetting adaptations

I have not tried the ZIP kit for the valve body yet.

Is this normal on the diesels? Would a ZIP kit or valve body rebuild fix this? Or am I looking at a full rebuild?

Thanks!

[andrewwynn]

This happens in any gear? Video shows going 40 and slipping below 1500 or so.

My xm doesn't grab below 1200 from launch but I've never noticed any issue in other gears.

I can do a test in m/s mode and see if this happens in other gears but you already did what i would suspect should fix it.

Does suggest torque converter to blame which if the case I'm gonna be really upset at myself since i recently replaced my whole motor and had my torque converter in my hands!

[scottgun]

It does happen in any gear. And it was slipping up to 2500 rpm before I let off the gas.

I did discover BMW intentionally allows slipping to warm up the fluid faster. So I checked the transmission fluid temps in BimmerLink and the temp stays at or below 60C. Since the running temp should be above 90C, the fluid doesn't get up to temp to disable the warm-up slipping.

I am guessing the cooler thermostat is stuck open, so I've got a new one on the way.
Until then, I flashed the transmission with xHP and disabled the warm-up procedure. The slipping has improved significantly. Only slipping a little now when starting from a stop, which I think is normal for these cars.

[andrewwynn]

Like i mentioned below 1200 RPM no grab for me. Also when it's bitchn' cold out it'll stay in a low gear to warm things up but i help it by driving in sport with the heater off so the coolant pump will run slow and the ECT will climb 2-3x as fast. No grill flaps in 2011 so i will add cardboard in winter 1/2 to 2/3 the radiator not the intercooler.

I was curious what normal range of temp is. Chat GPT result:



Mine has been much cooler when i peeked recently but it's been single digits outside. 4° literally the last time i checked


–awr–

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[Henn28]

I emailed ZF some time ago about normal temps on the 5hp when contemplating an upgrade to the “cooling” system and they replied 170 to 190 deg F, so roughly 77 to 88 C.

I assume it’s similar for the 6HP?

[andrewwynn]

Looks very similar to chat GPT result


–awr–

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