Transmission Issue - lurching into lower gears during decel

[hawkeye12345]

Tranny works properly at startup but once the tranny warms up it takes on a mind of it's own. The shift points change. I now have to take the RPMs over 4000 to get it to shift into a higher gear and if RPMs fall below 2300 then it shifts into a lower gear. Basically in-town driving is done at 3700 RPMs which can't be good on the engine.

On the highway (cold) all of the shift points are working and it will shift into 5th gear with no problem. Once it warms up it will drop from 5th into 4th at 65 mph+. I've tried to use the manual (steptronic) and it won't shift into a higher gear. It will show it going into higher on the display but once I release the lever, the display will show the current gear. I can still downshift with steptronic but not upshift.

This problem came on over the weekend. I took it into dealership and they found one code in the tranny which showed 'high temp reading' basically. They tested the tranny temp and it tested around 90 but the sensor was saying 140 - both in celcius I believe.

It happens 100% of the time once the tranny warms up. It is not intermittent.

I've read through a few other tranny threads and I'm thinking that it's the wiring harness with temp sensor that needs to be replaced but wanted to see if there were other parts that need to be replaced while I'm in there. Pulse Generators? Servos? Etc. Vehicle has 91k miles and has never had tranny fluid or any other service performed on the tranny.

Thanks

[Slavchob]

Have you figured out this problem? I have the same exact thing going on with mine, and can't figure it out

[TwinTurboGTR]

Slav, there is a known issue with the tranny doing this. Do a search and there should be a plethora of info there. Some say its warning signs of tranny failure and some say it was fixed by a software update.

[hawkeye12345]

Originally Posted by Slavchob

Have you figured out this problem? I have the same exact thing going on with mine, and can't figure it out

It was the small wiring harness that has a heat sensor embedded. Our local bimmer shop replaced the wiring harness and it fixed the problem 100%. We've been trouble free ever since.

[Slavchob]

What harness needed to be replaced? Also, where can I get one, and how much am I looking at spending? I've found a few threads that said the temp sensor needs to be replaced?? Sorry for all the questions, but Xoutpost is a little different from Audizine.

[alromcc]

Originally Posted by hawkeye12345

It was the small wiring harness that has a heat sensor embedded. Our local bimmer shop replaced the wiring harness and it fixed the problem 100%. We've been trouble free ever since.

Kindly advise the location or part number of the heat sensor.
Thanks a lot.

[JCL]

Originally Posted by alromcc

Kindly advise the location or part number of the heat sensor.
Thanks a lot.

For your 2000 X5 4.4, see this link. It is item #13, inside the transmission, connected to the valve body.

RealOEM.com * BMW E53 X5 4.4i A5S440Z MOUNTING PARTS CONTROL UNIT

That doesn't mean that this sensor is your problem, as any number of things can cause shifting problems and a proper diagnosis would be required to confirm if there is anything wrong with your wiring harness and temperature sensor.

[alromcc]

Originally Posted by JCL

For your 2000 X5 4.4, see this link. It is item #13, inside the transmission, connected to the valve body.

RealOEM.com * BMW E53 X5 4.4i A5S440Z MOUNTING PARTS CONTROL UNIT

That doesn't mean that this sensor is your problem, as any number of things can cause shifting problems and a proper diagnosis would be required to confirm if there is anything wrong with your wiring harness and temperature sensor.

thanks

[DrunkenNinja]

mine was fixed by a pan drain of the tranny fluid and reflash of older tranny software.