[Nhe261]

My 2008 335 E90 just got 50K miles, running good except the transmission will "jump" between 1 and 2. Just like the car was kicked from back. It is getting worse and worse recently.

I did lots of research of the AFT changing and finally decide to use Pentosin ATF-1 as lots of folks have successful results of it. Actaully I orderred Amsiol ATF already but scared by the different color and odor. So I ordered 20L Pentosin ATF-1 on Amazon, $201 with free shipping ($10/L) that's a good deal IMO.

Last weekend I did the first change, just open the drain and filled with the new ATF-1, i got 4L old oil out and pump in about 4.5L (the transmission cover is very oily I think there is some kind of leak, maybe the "jump" issue is low ATF level?). Anyway, after change i drived about 200 miles in all kind of driving, the "jump" issue is gone! The transmission is running much smoother than before.

I will keep driving for a week let the oil mix completely and wash all the bad thing out then do another change with the new filter/pan.
Plan to drop and fill at 15K miles interval later with ATF-1.

BMW's lifetime fluid is a joke. Maybe they are thinking lifetime is 100K. I think if i keep driving my car with the "jump" issue I have to change transmission at 100K or less.