E82 AT temperature problem!

[alberto.munizaga]

Hi everone!

Im from Chile, I have a 135i, a kick ass car!!! But i have a problem now...

I had to refill my AT oil because I have broken the oil pan. I replaced and my mechanic did the refill, and I supouse he did it in the right way (I bought the oil from BWM, the roght one, Im sure of that). BUT now I´m going to track days, and in the lap 10, the gearbox start to change the gears very slow, and is hard to the car to get up the RPMs....

If I still running, the light of gear box temperature turn on. So i have to let the car cold to run again. Do you know why this is happening? is normal in the car when you go to trackdays? or may be i have a problem with the AT oil level?

My car is a 135i, E82, 2010, AT gearbox, 6 gears. AT model ZF 6HP19

Thanks!!

[alberto.munizaga]

I think my mechanic could overfilled the gearbox... how can i measure the level? just taking out the fluid?

[Stan.mac]

Trans Oil cooler????

[froop]

I know I've replied to your PM already Alberto but I figured I might as well post my thoughts here for others to see.

It's unlikely it is overfilled as that is almost impossible unless the car is on a tilt when filling. Under filling is possible but I'm sure that any mechanic worth some salt should know to fill it up until it overflows out of the fill plug as well as fill with the car level.

Most likely the fluid is just overheating from 10 flying laps in a row. If you want to be able to do continuous flying laps you'll need to invest in an aftermarket transmission fluid cooler. I'm not sure if there are any products out there that are bolt on or whether you need to custom build one. Either way, I think that this is the way to go.

When I took my 6AT out to the track I didn't have this issue mainly because I didn't reach 10 laps due to the session being less than 20 minutes long. Also I would probably run a relatively easy cool down lap every 5 laps or so. That won't help cool down the transmission so much due to lack of a dedicated cooler but it should slow down the heat buildup so that you can run more than 10 laps.

[135Pats]

Originally Posted by froop

I know I've replied to your PM already Alberto but I figured I might as well post my thoughts here for others to see.

It's unlikely it is overfilled as that is almost impossible unless the car is on a tilt when filling. Under filling is possible but I'm sure that any mechanic worth some salt should know to fill it up until it overflows out of the fill plug as well as fill with the car level.

Most likely the fluid is just overheating from 10 flying laps in a row. If you want to be able to do continuous flying laps you'll need to invest in an aftermarket transmission fluid cooler. I'm not sure if there are any products out there that are bolt on or whether you need to custom build one. Either way, I think that this is the way to go.

When I took my 6AT out to the track I didn't have this issue mainly because I didn't reach 10 laps due to the session being less than 20 minutes long. Also I would probably run a relatively easy cool down lap every 5 laps or so. That won't help cool down the transmission so much due to lack of a dedicated cooler but it should slow down the heat buildup so that you can run more than 10 laps.

Inclined to agree with this. OP it's likely your torque converter is producing too much heat. There is such a huge difference in terms of wear between highway pulls and full on track driving, they're not in the same universe of mechanical stress and load. There are no bolt on AT coolers for our car, to my knowledge.

[alberto.munizaga]

damn...... thanks a lot..... very sad.... I bougth the car to run it on the weekends!

Alex, question, how many take takes you to ride 1 lap? my are 1 minute lap, so I only run 10 minutes, and you told me you have ride 20min without the problem? How is the whether in the track race? hot, cold?
Thanks!

[alberto.munizaga]

hi every one....

My solution to the problem!

So, I would like to change my oil trans for a better one to trackdays, some recommendation?

Thanks!

[135Pats]

@alberto.munizaga Sorry don't quite get what you are saying here, is your goal a dedicated transmission cooler? Or do you simply want to try a more shear resistant transmission fluid?

[moveswiftly]

I've done more than 10+ Laps in 100 degree weather with my AT. No overheating issues ever.

[alberto.munizaga]

Hi, is my goal to keep the AT fluid cold....
chesterfan1230, what version of 135i do you have? what AT do you have? double clutch? can you do the Launch control? becuase with my AT i can´t.

[Dackelone]

Originally Posted by froop

...It's unlikely it is overfilled as that is almost impossible unless the car is on a tilt when filling. Under filling is possible but I'm sure that any mechanic worth some salt should know to fill it up until it overflows out of the fill plug as well as fill with the car level.

^^Not only THAT, but the engine needs to be running and the trans needs to be in neutral or drive(car up in the air LEVEL!). Then you pull the fill plug out and add fluid until it starts to spill out. I think the trans fluid also needs to be in a certain range too. ~80'C I think. ?

Besides changing the AT plastic oil pan did you also replace the valve body filter? Or did your mechanic reuse the old filter? You should also clean out all the gunk that collects on the magnets inside the pan.

The California Transmission Supply Company is a good source for BMW/ZF fluids and knowledge.
http://www.thectsc.com/catalog/6hp19/21-7.html