[daps87]

Hey everyone,

So back in the day I bought a 2012 E90 330d LCI, without iDrive, pre-owned. She's absolutely beautiful and an absolute pleasure to drive. Sure, she's had problems of her own but there's one problem that's been persisting and I just cannot get my head wrapped around it.

It is fitted with a ZF6 auto box. Initially, after I bought it, I had no problems with the box. But soon enough I started experiencing the main problem: Whether the box is in D or DS, at random times, when you put your foot down just slightly more than normal (to get an oomph on take off), the box shifts automatically back to 1st and off we go. But it doesn't let go. It stays in first and the revs eventually starts redlining. For about 3-5 seconds, it'll stay like that and then all of a sudden the computer realises its supposed to be shifting. And then it goes down 2nd, 3rd and so on.

I tried to match watch I could find on Google to my problem and we ended up spending a fortune on new oil and filters from ZF. That seemed to have solved the problem, but only for a while.

It started doing it again a short while after that service and it's been doing it ever since. It does seem however that its occurrence has started increasing in the last couple of months. Instead of experiencing it maybe once every 3/4 days, you experience it now almost once per driving session.

We've had it plugged in to read any potential errors off of the computer, since nothing is showing on the dash. Everything seems fine with the exception of a temperature sensor that seems faulty inside the box. Could this be it?

My worry is that when this happens, I usually put the box into DS mode and immediately shift down (from D -> DS -> M2) but the computer doesn't respond. On the dash it shows me that I've selected M2 or M3, yet the engine is overrevving and the box is stuck in 1st.

I can usually combat the problem by simply easing off the throttle until it decides it'll shift. Or I have to pull away gently in either D or DS modes, or I have to manually control the box (not very economical in daily traffic).

I would appreciate any thoughts you may have.