Hello, new poster here, been a member of BMWCCA for about 5 years, just never posted. I have a '02 330ci Sport Package, M wheels, a real beauty that has run great for a while now, but my wife has an E83 '04 X3 3.0i that was running fine until last summer. About 6 months ago, we started getting sharp, jarring stuttering under acceleration. At first, it was rare, but it progressed to being consistent by late fall. The issue only occurred under acceleration (torque applied), and was gone completely in high gear on the highway. I thought at first that maybe the clutch packs in the transmission were wearing out, and that an AT rebuild would be necessary. But, the weird thing was that this sharp stuttering was the same both at medium and high torque (i.e. whether accelerating gently or flooring it). If it was the AT clutches, it should have been worse at higher torque, I thought. Thankfully, I know a former BMW dealer tech who's out on his own now in the Saint Cloud/Kissimmee FL area, so I had him go for a drive with me with his laptop and dealer-level software hooked up to the OBD-II port. He right away told me that it wasn't the transmission. He started talking about the transfer differential for the AWD. He did some scanning & testing as I drove, and said that the little electric motor inside the AWD transfer differential wasn't responding to queries, but that its control board was. We stopped, he reached under the car for a bit and disconnected the power line to this little AWD diff electric motor, and bam, problem was gone... with the caveat that only the rear wheels now would have drivetrain power to them and the little "4x4" light would stare at us from the dashboard. He tried to see if maybe we could replace the little motor by itself, and contacted some folks. However, that is apparently a no-go. So, where I'm at now is trying to find this piece to replace. I'd like to get the BMWCCA community's opinion(s) though. My questions are: 1) What the heck is this electronic differential for the front-rear axle power transfer called? What's its exact name? He didn't know the exact name either. 2) How does a little electric motor cause this apparently $2k differential so much grief? 3) Is it common for this little motor to fail? Anyone else have troubles with (what I'm going to call) this AWD power transfer differential? According to my tech friend, this piece is supposed to be a lifetime part... so I'm guessing this failure is rare. 4) Naturally, the car is out of all warranty at 6 years old, so does anyone know where I could find this differential, new? My tech is looking, but two searches are better than one. Thanks for any help you can provide. I'll check this post daily for any replies or questions you have for me. ~H4mmerDown
I know on a Chevy Blazer they call it an "encoder motor", BMW may have a different name for it though, very common failure on Blazers, never heard of one going on a BMW though
Talk to your service manager and ask for BMW to participate. They will likely offer to pay for the part and you have to pay for labor to have it installed by a BMW dealer.
06 X3 has exact same issue with jerking under load. My Wife's 06 X3 has the exact same problem. I looked around the web and the problem seems to be widespread. My car is still under warranty but BMW will not admit that there is a problem. I had it at two different dealers on three seperate occasions and they say they can't reproduce the issue. I took the service foreman out for a ride to show him the issue and he finally admitted that he felt the jerking. After that they had it for a couple of days and now are telling me that my gas has to much ethanol in it and that's the problem. I put CAM2 in the car and it still has the same problem. I'm very frustrated with BMW at this point they have excuse after excuse and everytime i prove them wrong the excuse changes and my car still jerks. The service rep said they have all kinds of issues with high percentage of ethanol in gas creating problems in BMWs. Did you find the electric motor for your differential? If this fixes the issue I will keep the car otherwise I'm through with BMW and their BS. This is the worst experience I have ever had trying to get any car repaired. I know i have more questions than answers but it doesn't seem that anybody can fix this issue and BMW will not admit that it's an issue.
BMW would not admit there was an issue with the tranny. Well after going around and around with the dealers telling me this jerking is normal for an x3 i gave up and BMW of NA won. I'm sure they hope other people do the same thing. It's unfortunate because i have been a loyal BMW customer and would not buy anything else but that has changed. BMW has lost a customer for life. My wife's new car actually has a transmission that is not sealed for life and i plan to have the fluid and filter changed at 40K miles just like the maintenance schedule says. Imagine that a transmission that actually needs service.
Hi, I believe that your problem might be a transfer case motor failure. BMW calls this an "actuator " part # 27-10-7-566-296. if you shop well, they go for about $700.00 (PASSPORT BMW) with the club discount. I believe that shop rate is about 4 hours. Also you will need to change the Transfer Case Fluid and make sure that the internals in the case are not binding and causing the motor gears and causing a failure. And by the way this is not a BMW issue. It's a "chit happens" issue, so go up stairs, put your big pants on and suck it up. It's still one of the best cars you have ever over owned.
