BMW Transfer Case Actuator Problem and Fix
BMW Brake, ABS, and 4x4 Warning Lights Come On
This article is an attempt to aggregate information in a single place regarding a defect in the X drive systems of BMWs that will typically affect ALL of the following models of BMWs at one point or another, typically around 80k-120k miles:
- 2004-2007 BMW X5 E53
- 2004-2010 BMW X3 E83
Make sure to check your model to ensure it has the same actuator motor and gear as described here and in the videos below.
I include here a description of the problem, links to outside information and some information on my own experience fixing this issue on a 2006 X3 E83 model. This article is for informational purposes only and the reader assumes all responsibility for attempting to fix without professional assistance.
Having said that, with some basic automotive acumen and a few hours this issue can be fixed for as little as $50 or less to replace just the transfer case actuator gear whereas a mechanic or dealer would conceivably charge $1,500 to $2,000 or more to replace the transfer case actuator motor entirely (or worst case scenario attempt to replace the entire transfer case?).
Transfer Case Actuator Motor Replacement Gear
Indications/Symptoms of the Problem
- The brake, ABS, and 4x4 warning lights all come on at the same time (see title photo above)
- There is an very audible rapid clicking noise that comes from the transfer case (approximately under the driver's seat underneath the car) just after the engine is turned off. The best way to hear this is to open the driver's side door when parked, turn off the engine and listen for the clicking noise (it may not happen EVERY time so try it a few times). The noise should only last about 1-2 seconds, see the video included here for an example of the sound.
If you have both of these symptoms then the culprit is very likely to be a stripped gear inside the transfer case motor. The transfer case actuator motor is a small motor that is bolted on to the transfer case and can be removed and replaced (or repaired with a new internal gear).
If you DO NOT hear the clicking described the cause could be something else (not covered in this article).
Watch this video for an excellent description of the problem and removal and replacement of the transfer case actuator motor:
BMW Transfer Case Actuator Motor Gear Problem in Detail
So what's going on inside the transfer case actuator motor? In short, there is a nylon (ie: plasticky) gear inside the motor that is turned by a metal worm gear (a screw). Over time the nylon part gets worn down and stripped and does not turn any more. See the photos.
There is a lot of discussion in various forums about how this gear does not ever seem to turn all the way around and you can fix it by simply rotating the gear to the unused portion (a potential free fix). I cannot speak to whether that is a reliable long term fix since I did not try that. You can see from my photos however, that it indeed does not look like one side of the gear that still has the light green lubricant on it was ever touched or used by the worm gear,so take that for whatever it's worth.
My experience (and decision) was that if I was going to spend an afternoon underneath the car removing the actuator motor and taking it apart I did not want to risk the free fix failing at some point and having to do it all over again. I believe it's well worth the $50 - $100 to purchase a new gear and not worry about it for another 80k miles or more. Since the first writing of this article, replacement gears have actually gone from $100 down to $20 or less!
Fixes for the Problem
If you've determined from watching the video above that you have this problem you can fix it yourself by either replacing the entire motor unit (still somewhat expensive at $800 or so just for a new motor), or you can go a step further and replace just the motor gear by following along with the video below. You can order a new gear easily on Amazon with the provided link.
Actuator Motor Gear Replacement
My experience is that it took me about 3 hours to remove the actuator motor and disassemble/reassemble it and bolt it back on to the car. The hardest part was really just accessing the motor and torx bolts to get them off. Some basic tips would be:
- Make sure you've let the car cool significantly (overnight would be a good idea) before attempting.
- You may need some special female torx (star) socket bits for the bolts that hold the actuator motor on (link below).
- Some universal socket joints for accessing the torx bolts (I had a hard time getting my socket wrench to fit in the space, only was able to do it with a universal joint).
Another Good Video on the Problem (X5)
This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.