Trans fault codes help

[stephan m]

Hi, I have recently purchased an old Z4 2004 e85 auto. it has done 168k miles. I decided to do a transmission oil and filter change! I drained the oil, removed the pan, cleaned all the magnets and sludge. replaced the pan filled the with oil. put plug back in. started the engine and moved it through e gears. turned it off and rechecked the oil. Topped it up a very small amount. Went for a drive and the trans light came on. Within a minute the car went into limp mode. Just made it home. There were a number of codes. I forgot that the battery went flat before I started the change I jumped it and drove it to warm it up. Trans had no issues before the oil change! I haven’t driven the car for a couple of Months. The trans fault showed fault codes 31 gear monitoring, 36position sensor gear. I cleared the codes. I look on line and realized that I should have had the car running to complete topping up the trans. I did this. But when I opened the drain plug oil came out ? I ran through the gears with it running and re-topped the trans and put the plug back in.
Went down the road. Within a mile I the light came on again. Went int slump mode. Now it says an additional code ,30 converter lockup clutch excessive slip p0740, p2761,po741.

Looked online and tried a few things:
Reset adaptive trans settings but turning ignition on and holding accelerator down 30 sec
Disconnected the battery for 5 mins. reconnected and cleared the codes
I used Valvoline Max Life oil! not sure if that is an issue?
Any suggestions on what to try or test next?

 

[Rucky]

I changed the auto gearbox oil and fiters on a 2.5 04.
Drained it hot , replaced fikter etc.
Filled until it spilt out the filler then started the engine and let the gearbox oil come up to temperature.
I then kept filling whikst cycling the gearbox through each gear - someone in the car and someone underneath pumping oil in.
I sopped when the oil was at operating teperature and oil spilled from the filler.

I used Castrol - there were no issues at all afterwards - maybe try Castrol , was it Syntrans or Syntrax? Go to Castrol oil finder and put in your reg.

 

[stephan m]

thanks for the feedback

 

[stephan m]

I changed the oil again and used Castrol. I cleared all the faults and went for a drive. It seams that the fault comes when the car gets into 3rd gear . Still getting 31 gear monitoring and 36 position sensor gear. faults then a few minutes later the Trans light comes on in the dash. ! i don't understand why changing the oil would do this. The only other thing that may have been the course is i sprayed some degreaser on the engine sump and the trans sump. then rinsed it off . The rinsing may have caused the ele fault???? so frustrating .

 

[Rockhopper]

This is one reason why changing the fluid is not recommended unless you are chasing a problem.
Gear position sensor is a common fault and the part is about £180 I think.

 

[Rucky]

I don't think the fresh oil caused it but maybe not filling running resulted in operating underfilled and this is what caused the damage? Oil comes out the filler static but level goes down when started, fully charged and primed. Worth checking all the connections / plugs. Guess the sump has to come off to check the internal position sensors and electrics.Sorry can't be of more help

 

[Rockhopper]

The position sensor bolts onto the side, its easy to change. There is a couple of litres of fluid in the torque converter that you cannot drain as well.

 

[DashingDaryl]

This is one reason why changing the fluid is not recommended unless you are chasing a problem.

It is always a tough call for me about whether to change the oil or not in a high mile car. Here is a video that explains the situation.
https://youtu.be/o690DovjDAc
Sometimes I just drain a couple of liters and replace those, so I don't do a full flush but refresh the transmission oil.

 

[stephan m]

thanks for info . i plan to change the gear position sensor when i find out the part number and where it is located. dose anyone know the model of a z4 auto trans 2004 ?

 

[Zulu4]

This is one reason why changing the fluid is not recommended unless you are chasing a problem.
Gear position sensor is a common fault and the part is about £180 I think.

Fully agree.
With auto boxes, 'if it ain't broke, don't fix it.'

 

[Rucky]

You may find this of interest.
It's from ZF - I followed their advice.
https://aftermarket.zf.com/sea/en/aftermarket-portal/passenger-cars-and-lcv/know-how/useful-tipps/transmission-oil-change/