Transmission problems, help needed

[Godzi]

Hi everyone,
I am new member but I was reading a lot on this site before I registered and I see there is a lot of knowledge here.
I bought 2003 X5 4.4i with transmission problem, I am mechanic and I have no problem fixing many things including engine but I am not very familiar with automatic transmission.
I will try to explain what is going on as short as possible.
Car starts good cold or hot, but transmission works fine when cold, after 10min of drive it suddenly revs rpms and goes to fail safe program with hard bang to 5th or sometimes to 4th gear. I have scanned it and there is several things showing up.
Transmission temp is -55c
Replaced harness in transmission and still same reading.
Solenoid 3
Map cooling activation
5A brief power interruption
Dynamic stability control
And also weird wheel speed reading when parked it is showing
LF 0, RF0,
LR 4850 rpm
And no RR wheel at all.
Is there anyone who had this kind of problem and is there solution to this.
I just want to make sure that problem is transmission it self not something else causing it to fail.
Excuse my English, it's not my first language.
Thank you in advance

[andrewwynn]

Crazy abs readings and DSC errors often from internal design flaw in the abs module.

Make sure your connector is clean to the transmission but I think you said you changed the harness so that's not likely the problem.


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[Godzi]

Thanks for reply
Yes I have replaced harness and plug looks like new and harness in general,
Didn't find any particles in oil pan, I am just totally confused with temperature reading and fact that it drives totally fine when cold, it shifts nice and manual shift works as well.

[Purplefade]

May try swapping the left and right rear wheel sensors and seeing if the error follows the sensor. RR 4850 LR0. It’s possible it’s shutting itself down because of the drastic difference in the speed sensors.

I know you can clean and recalibrate those as well but you’d need a laptop with the bmw tools apps on it...

[Godzi]

That makes perfect sense, I will do that first. I have to try all options before I remove transmission.
Can it be something wrong with TCM as it's reading ATF temp as -55 always, and even engine temp after 1 min. idling shows 124c.

[andrewwynn]

The transmission suoerman said the harness sensor can read off and not the biggest concern but your is seemingly reading min temp so either open or short so I would track down which. If one wire shorted likely others.

You said you replaced the harness. So you mean inside or outside ? The temp sensor is part of the inside harness iirc.


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[Godzi]

I replaced inside harness, hoping to get different results and move from death point but nothing changed.

[ahlem]

Trace the wheel speed sensor wires from the wheels through to the harness all the way to the connectors. Others have had problems with cracked insulation and grounding out and getting odd issues with ABS and transmission. Mine only happens when it rains and I'm trying to track it down currently.

[Godzi]

It looks like some wiring issues, I cant believe to have so many different codes and all wrong readings.
Thanks for advice

[andrewwynn]

Originally Posted by ahlem

Trace the wheel speed sensor wires from the wheels through to the harness all the way to the connectors. Others have had problems with cracked insulation and grounding out and getting odd issues with ABS and transmission. Mine only happens when it rains and I'm trying to track it down currently.

Transmission error when rain or wheel sensor?


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