e46 325i gearbox temp sensor

[hongbk]

hi there, i would like to know if anyone has experienced fault on gearbox high temperature warning alert? The sensor detects a reading of 100degC. This is on a 2004 325 auto model, mileage at 82500km. What could possibility be the fault?

 

[Impulse]

Dear Bro hongbk,
If you had temp like that when water turn to steam,I suggest you drive your car to the nearest mechanics. To ignore this will cos gearbox seizure and oil leak.
At this stage, you will require your g/box n pump overhaul.Damage will be around 3k+++ .poorer! so better don't try.
Did you service your g/box oil n had the oil pan removed and clean out the sludge? Accumulated sludge can clogged up your heat exchanger,you know, the little radiator attached to the rear of the main radiator? It just like cholesterol building up n giving the pump a hard time until it konk out.
Chk with mechanic whether you can flush out the heat exchanger as well. If not,
replace it with a new one.
Hope this will help.
coutesy of my wallet.
regards,
Impulse

 

[hongbk]

Dear Bro hongbk,
If you had temp like that when water turn to steam,I suggest you drive your car to the nearest mechanics. To ignore this will cos gearbox seizure and oil leak.
At this stage, you will require your g/box n pump overhaul.Damage will be around 3k+++ .poorer! so better don't try.
Did you service your g/box oil n had the oil pan removed and clean out the sludge? Accumulated sludge can clogged up your heat exchanger,you know, the little radiator attached to the rear of the main radiator? It just like cholesterol building up n giving the pump a hard time until it konk out.
Chk with mechanic whether you can flush out the heat exchanger as well. If not,
replace it with a new one.
Hope this will help.
coutesy of my wallet.
regards,
Impulse

Dear bro Impulse,

Thank you for your valuable points and i will take note of the items that you have mentioned and let's see what needs to be done.

 

[stan001]

Hi,

Can you read more about the gearbox temp sensor at the URL below :-

http://www.g-w.com/downloads/samplechapters/426-4_AT&T_Ch14.pdf

 

[planta]

stan001
Great sharing bro.

planta

 

[astroboy]

Auto gearbox will heat up beyond normal temperature when your auto clutch packs start to slip. Such heat will boil and cook the ATF and it will turn black due to the excessive carbon deposit.

Most auto cars inclusive of BMW has 2 pressure pumps to force the clutch pack onto the flywheel. Low pressure pump is to facilitate shifting. Weaken pumps will cause clutch pack to slip and ATF temperature will raise.

BMW gearbox is designed to slip more compare to JDM so the shifting is smoother. Thus wearing the clutch packs faster but BMW clutch packs has more clutch linings than JDM. Since the clutch packs is a wear and tear item, there's limited life span to all gearbox and BMW GB is not spared. Its a matter of time, your day will come. Some will experience it earlier than others. If not 3 years, then it will be 5 years. Like death, something we cannot escape.

I have friends been avoiding auto BMW for this reason.

Do u have an ATF dipstick? If JDM, I can tell very easily.

If I were u, I will wish for a faulty temp sensor. Otherwise, jia lat lio..

Can give us a brief intro on your gearbox? Is it still on "LifeTime" ATF? Have u replace them before? When? Using what ATF? done at which workshop? Is your 2004 E46 325i a CBU or CKD model?

 

[damontwb]

Two things check thermostat condition (replace one if damage), else check the gearbox harness some electronic circuits mainly controlling the gearbox temp.