automatic transmission

[diib]

I have bmw e46 325i 2002 . from time to time , The transmission make a strong sound or duck when every gear in the gearbox moves forward or backward. Sometimes it lasts for a while. When I turn off the car for some time, it will return normally .but i realized that that problem occure only when the car heat in the middle not in cold . i made scanner and showed me this : "transmission: fluid temperature sensor".
if any ideas .. thank you .

[MauiM3Mania]

It would help those trying to diagnose the problem if we could hear it.... can you make a video and share it with us?

[RobertDenali]

When is the last time you changed the fluid?

[whiskychaser]

A faulty temp sensor can cause erratic shifting. It is part of the loom and I would want to see the live data before changing it. But to give you an indication, it has a resistance of 1k ohms at 25 degree C. If testing, check it at the TCM end as the fault could be in the wiring

[diib]

When is the last time you changed the fluid?

i have this car since june 2017 , i didn't change the fluid since then , and i have no idea if the former owner has really changed as well

[MarcoZandrini]

BMW put 2 different brands of automatic transmissions in the E46. One is made by GM of France and the other is made by ZF of Germany. They are different transmissions and require different fluid. The GM transmission uses Dexron3 or Dexron4. The ZF transmission fluid is a more expensive synthetic fluid. Go to E46Fanatics and look for a thread that lists all the approved fluids for both transmissions. The first thing I’d do is to drain and refill with fresh fluid. Also, check YouTube for a video by 50skid on how to change the fluid properly. These transmissions do not like too much or too little fluid.

[diib]

BMW put 2 different brands of automatic transmissions in the E46. One is made by GM of France and the other is made by ZF of Germany. They are different transmissions and require different fluid. The GM transmission uses Dexron3 or Dexron4. The ZF transmission fluid is a more expensive synthetic fluid. Go to E46Fanatics and look for a thread that lists all the approved fluids for both transmissions. The first thing I’d do is to drain and refill with fresh fluid. Also, check YouTube for a video by 50skid on how to change the fluid properly. These transmissions do not like too much or too little fluid.

thank you

[RobertDenali]

Start there and also change your trans fluid filter when you drain and refill. If it was me I would drain / replace filter/ refill , then drive for a month or two and drain / refill again to be sure the system has all fresh fluid.

[MarcoZandrini]

The fluid pan of the GM transmission has flat sides. The fluid pan of the ZF transmission is ribbed.