Code 59 Stalling Speed, P0721 Transmission output speed sensor on BMW X5 E53 2002

[AdrianX5]

Hello everyone,

New to the forum, so sorry if it`s not the right place to post.

I have a BMW X5 E53 2002 4.4L. It went to the mechanic to fix coolant leaks and oil leaks. They changed several coolant hoses (cooling and heating), expansion tank, seals, etc. Also, they changed the valves caps gaskets.
I picked up the SUV and next day I had transmission failsafe program on my dash; they plug their scanner and found P0721 (transmission output speed sensor).
I got INPA software, scanned the transmission and found code 59 ``Stalling speed``, which I believe corresponds to P0721.
Also, I scanned the engine and found Code 140 ``Output thermostat Map cooling`` and oxygen sensors.
To me, the engine codes, output thermostat Map cooling and oxygen sensors, are not related to my issue with the transmission.

Symptoms on the transmission:
Once the transmission in DRIVE, if I push the gas pedal, I feel the 1st gear slips, couple of seconds slipping, jumps, and then transmission goes to TRANSMISSION FAILSAFE PROGRAM.

I checked transmission fluid level, it`s OK.

I though the problem was the transmission output speed sensor, so, I did this test:
With INPA connected, I ran the vehicle slowly pushing the gas pedal so that the 1st gear didn`t slip and ran all the 5 gears without going into transmission failsafe program (I must say that it was practically without touching the pedal); and found that the output speed sensor is always sending RPM reading, depending on the gear; to me, seems to be OK. I could see the RPM on the output speed sensor higher for each gear, means higher for 2nd than for 1st; higher for 3rd than for 2nd, and so. If I push a bit the pedal, I can see the turbine speed going up but the output speed does not go up as fast as the turbine speed (means slipping).
Also, I found that, it`s not on 1st gear that it would slip; while doing the test, I found that it would slip in all gears if I push the gas pedal.

1) So, what do you think it`s wrong with my transmission?
2) Where in my transmission could I plug a manometer to read the pressure sent to my valve body?

Thanks a lot for your opinions.

[anthonyk03]

idk i have same issue

[flyfishvt]

Stupid question but did you clear all the codes? Which ones came back?

[anthonyk03]

p0731 and p0732 also P0721