I have a 2006 530xiT Sport Wagon. I bought it approximately 5 years ago, from the original owner, with approximately 64,000 miles on it. It currently has 217,000 miles on it.

A couple of weeks ago, it started "kicking" at low speed. "kicking" is the best way I can describe what it's doing. It's very slight, and it only happen when the car warms up. I've brought it to my mechanic, and he's changed out the filter/screens in the transmission, and has done two transmission flushes/refills on it.........and it's still happening. It's not throwing any codes, so we're unsure what to try next. Everything else seems to be fine. It shifts smoothly otherwise, and the transmission doesn't seem to be slipping at all. It only happens under power, and at speeds between roughly 20 and 40, when the car has been run for a while, and it's warmed up. In the morning, after the car has sat overnight, it doesn't happen.

It's also intermittent. Sometimes it doesdn't happen at all.

Any ideas/suggestions?

 

Hello- is this happening while the transmission is holding a gear, or is it associated with a gearshift? Does it seem to be more associated with heavy loads (hills/hard acceleration), or does that not matter? Just to be clear, this started happening before you had the transmission fluid serviced, correct? Any sense of whether the transmission fluid has ever been changed by a previous owner?

As a starting point, I'd ask your mechanic whether he happened to inspect the adapter (no. 2 in the attached diagram) between the mechatronics unit and the transmission. Probably not, since this requires removing the mechatronics, but this is a high failure item. It will crack, and when the transmission fluid warms up and thins out it will seep through the crack and cause issues. Given your car's mileage, I wouldn't be surprised if it's been replaced at least once already (I think mine went at around 75k miles). However, when this happened to me, the car would go into limp-home mode and throw codes, which yours isn't doing. You might be catching it early, or it could be something else. The good news is that if it is the adapter, it's a cheap part, but the bad news is it'll require another transmission drain and fill. There are DIY procedures out there as well (I did mine), but it's messy and just like with so many other procedures having x-drive makes it significantly more painful than on a RWD car.

(Please note I grabbed this diagram using my VIN, so don't take the part no. as gospel truth for your car)

If it's not the adapter, it could be time to replace one or more of the solenoids in your mechatronics unit. There are lots of threads out there describing options, DIY procedures, cost, etc.

Are you using a BMW-specific code reader to communicate with the transmission module, or a generic OBD-II reader? Transmission codes wouldn't show up on a generic OBD-II device.

TBH, since you've recently paid for 2 transmission services, I'd be tempted to just drive it for a while and see if it gets worse or finally throws a code before ripping into the transmission, depending on just how bad the driveability is.

 

Hi, Thanks for the reply.

I'm not sure if this issue happens while holding a gear, or if it only happens during gearshift. It happens at such a low speed, that I'm usually out of it pretty quickly. I checked again today, and it seems to be happening roughly between 10 and 25 mph, and doesn't seem to be any more associated with heavy loads, hills or hard acceleration than regular driving. And, as I said earlier, sometimes it doesn't happen at all......even after driving it for a few hours.

Yes....this started happening before I had the transmission fluid serviced. I'm not sure if the previous owner had the transmission fluid changed or not. My guess is no, due to the relatively low miles that I bought the vehicle with. 64,000

I'll ask my mechanic whether or not he happened to inspect the adapter, but my guess is not. The first time, he basically just changed out the transmission fluid and cleaned a screen. The second time, he changed out the transmission fluid and changed a screen. The one that's part of the transmission pan itself.

I'm fairly certain that my mechanic is just using a generic OBD-II reader, as he's not really a BMW mechanic. Another customer of his has 2 530iX Sport Wagons....a 2007 and a 2008, as well as an older BMW wagon, so he's been working on these for a while, though.

The driveability is not bad at all, so I'll probably just drive it and see if it gets worse. As it stands, I'm all ready $1200.00 into this. Thing is, I drive a lot, and really don't want to find myself 1,000 miles away from home and have a catastrophic failure. I guess that could happen with any car.....even with much lower mileage.

Anyway, thanks again for the advice. I'll talk to my mechanic about the adapter.....as well as potentially replacing one or more of the solenoids in the mechatronics unit.

 

Two weeks ago the "kicking" just stopped. It would seem that the transmission flushes did the trick. Something must have been gummed up from the old "lifetime" transmission fluid with 200,000 + miles. Hopefully the issue is resolved for good, and I'll be able to get at least another 50k miles out of the car.