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Transfer Case Actuator potential free fix!

790K views 1K replies 251 participants last post by  jayram1408 
#1 ·
A couple weeks ago, I got the "terrible triad" of lights (ABS, 4x4, and Brake). Recently, I got the clicking noise after turning the car off and was able to determine that it was coming from a transfer case. Using several posts from here, especially this one:

http://www.bimmerfest.com/forums/showpost.php?p=4473836&postcount=19

I bought a new transfer case actuator and installed it. Problem solved, no lights, no clicking, all better. It is not a cheap part at 720 bucks from getbmwparts.com, and 900 bucks elsewhere, so the engineer in me wanted to figure out why they were failing.

Which brings me to the purpose of this post. I disected the old actuator to find out what the heck is going on inside it. I appologize for the huge pictures, but some sort of resolution was needed to describe what I was trying to say.

What the actuator looks like when off the car:


And broken down into the pieces: Bottom right is the motor, top right is the brush assembly, top left is a guard of some sort that pops off (albeit bent and unusable once you have it off) and the bottom left is the gear assembly (we'll focus on this one)


After I popped off the oil guard piece, here is what the inside looked like, a ton of shavings and grease.


and closer:


So you can see the motor turns a worm gear which is mated to a black gear (which is made of plastic :thumbdwn:!!!) Eventually, this gear wears down like crazy and doesnt have any teeth left to grip the worm gear. This is what causes the slipping, and the error lights, and especially the clicking sound.

In this photo, you can see the change from good gear area to the bad area. The good area is on the left, and as you follow the black gear around to the right, you can see where it has been worn down from sitting all the time.




So, I went farther. I took off the black gear to see what it looked like:
Good side (what it should look like everywhere):


Bad side (Cause of the problem)


POTENTIAL SOLUTION:

So now we know what the cause is, how can we fix it? It has been (from my research) that everyone just buys a new actuator. Yes, it fixes the problem, I can vouch for that, but I don't know how many other people looked into what CAUSED the problem.

I bet you could unbolt the motor from the gear housing assembly (it is held on by 4 torx bolts that come off quite easily compared to trying to remove the actuator from the car).
Mark a location of the current position on the white plastic gear you can see in the first photo. After the motor is unbolted and removed (ONLY THE MOTOR, DONT DESTROY YOUR ACTUATOR AND TAKE THE WHOLE THING APART!!!!), turn the white plastic gear 180 degrees from its current location. This takes the bad part of the gear and puts it where it will not get used, which means that a good part is now in contact with the worm gear.

Re-insert the motor and bolt back together. This should give you, say another 65k miles (when mine failed) or so before you likely have to replace the actuator. Re-install on your transfer case, and voila! you should be good to go with only an hour or so of your time wasted instead of time and 900 bucks.

I haven't tried this, so try it at your own risk, but with pulling everything apart, it seems like a pretty safe bet, but obviously I can't be held responsible if something does go wrong.

Hope perhaps it can save someone almost a thousand dollars. I believe my logic is sound, but I look forward to your comments!
 
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#129 ·
I have scepticism about the kit using the bronze gear. Cldchc the kits uses another forum members pictures to aid in the sale and not actual pictures of the gear or kit. Your post count is low your also listed as being from Italy, that leads me to believe that you might gain in some way from a sale of the kit. My most worrisome part is you clearly stated you bought and used this part on your x5. On the XOutpost forum you said the kit listed in the auction was yours and you would produce and ship the part and it was tested since 2011. All these things lead me to think this is a scam, if I'm wrong please prove it to me and post the pictures you should have of your kit packaging ,the gear and the instruction.
 
#130 · (Edited)
"I just found this company over ebay that sell a service and will refurbish your actuator (ebay item130639752074) for $200 with one year warranty so its much better than
just buying the gear and its in USA not italy. i alrady bought the service. if the gear was less expensive i will go for it... but this is not the case"

Please keep us informed of this and what your results are. Do you happen to know what material will be used for the new gear? Thanks
 
#132 ·
so i actually replaced my motor with a new one after trying this fix (as it stopped working after a week). The 3 lights of death went away... so i've been driving for a month now, and I had to disconnect the battery for some reason. When i reconnected and turned on car, the 4X4 and brake lights came back on! what gives! the car drives fine, so not sure why those lights would come back on after I disconnected battery....
 
#133 ·
I've benn reading this fix for some time now, and it's great to know that when i see those dreaded 3 lights at the same time, there is fix around it. However, i've been wondering whether has someone been able to find a replacement chain of the same quality that bmw uses in the transfer case, just to avoid possible worse damages by using a metal one that some people have suggested?

Is it possible that this sort of plastic gear is common to some other application that could become a vheap donor option? I guess those of you that have opened up the actuator might be able to know more or even have been able to track down a serial number that could give us a hint!
 
#134 ·
... Is it possible that this sort of plastic gear is common to some other application that could become a vheap donor option? I guess those of you that have opened up the actuator might be able to know more or even have been able to track down a serial number that could give us a hint!
Well, that's the $64,000 question, so to speak...

The exploded parts diagram of the transfer case on RealOEM does not take it down to the level of component parts for the actuator assembly; it just shows that assembly (which, if I'm reading the diagram correctly, also would include the plastic gear in question) as P/N 27107566296 (in the case of my 2007 X3) -- an $800+ part! :yikes:

Obviously, these plastic gears are produced somewhere for use in the actuator assembly; the fundamental question is: who produces them...? In re-examining the original photos posted by "pburnett," it looks like the actuator assembly may be sub-contracted to Bosch -- or it could just be the motor itself that's built by Bosch... :dunno: That might be the place to start, though... Ultimately, someone somewhere builds these OEM plastic gears, then supplies them to whomever (perhaps Bosch) builds the actuator assemblies for BMW...

I submit that an appropriate 'kit' to economically refurbish the actuator assembly should consist of:
  • The OEM plastic gear or an equivalent reproduction, if one can be located or produced
  • The metal end plate that covers the gear housing ("pburnett" stated in his original post that it wound up bent and unusable after removal)
  • A fresh supply of whatever lubricant is inside that gear housing (looks like green jelly in "pburnett's" photos)
  • Instructions
 
#135 ·
A few questions

pburnett: First of all, we can't thank you enough for taking the time to help us with an inexpensive fix to an annoying problem.

I do have a few questions for you. I have the triad of lights, but do not hear any clicking noises after I shut down the engine. My indie guy is running his Chinese "Launch" diagnostic tool, and I am standing by, but he is leaning towards an this actuator issue as the culprit.

1. Do I need a lift for this repair or just a plain old set of ramps under the front wheels will do?
2. You mentioned in the very first post that it is not necessary to take the actuator off to turn the gear 180, but only the motor. How do you take just the motor off? It is not clear to me by looking at the pics...isn't there only one set of 4 bolts...are there two sets of 4 bolts instead - one set to thold the actuator to the car and another set to hold the motor to the actuator?
3. Roughly where underneath the car is the transfer case actuator located? I change the oil on my '04 X3 regularly, so that reference will be very useful.

Thanks very much in advance. We are very grateful to you.
 
#136 · (Edited)
1a no you might not , depends on your size. I'm 6'3" about 220 lbs and just did it laying on my back in the driveway in about 2.5 hrs.

2a yes there are four bolts holding the actuator to the transfer case and four more holding the motor to the actuator housing.

3a it's on the driver side just short of mid length of the suv. Towards the top of the transfer case.

Some stuff I noticed that might help, the brace that holds the transfer case in place can be loosen on the pass side( support it from under with a floor jack). Drop it about a inch to give a bit more room. Also a ratchet that has a handle that can control the ratcheting action will help remove the bolts easier in the tight confines on top. Finally the bolts are not just a normal bolt style. I believe they have a torx head style. So you would need a female torx socket set(I think I paid 14 bucks)not sure if I named the sockets right but I think the description fits.
 
#137 ·
hello guys this is my first post here!:wave: i have a x3 2004 and like everyone here all 3 lights came on.:thumbdwn: i didn't want to blow 750 on a new one so i took a chance on a used one at the salvage yard from a 2005 with 60k miles 400 bucks with 90 day warranty. before i installed it i opened both up just like pburnett did but i didnt remove the rubber seal!! the gear from the 2005 wasn't that worn out still i took pburnett advice and turned it 180d. i assembled everything back together and installed it myself NO MORE LIGHTS! Having the original worn out gear in my hand it does appear that it only works on one side, that being said im placing it on the hands of a professional gear machinist, buddy of mine! and hoping he can duplicate it by using the good side. as soon as i get the gear back (if he's able to make it) i will post pics of the gear and the assembly process and test it on my car. TO BE CONTINUED...............
 
#138 ·
... im placing it on the hands of a professional gear machinist, buddy of mine! and hoping he can duplicate it by using the good side...
Welcome!

Being a machinist, I suspect that your friend's preferred material of choice would be metal...? If you haven't done so already, I recommend that you go back and review this thread starting with some of the most recent posts (say, begin with #123), and ask your friend if he (or someone he might be able to recommend) can manufacture the gear out of the same material(s) as the OEM gear. This may be an important consideration to protect other components in the drive system/transfer case.

As a machinist, he might be better in helping to replicate the protective cover plate for the gearbox where this plastic gear resides, which reportedly gets bent out of shape when removed to remove/replace the plastic gear.
 
#139 ·
timfitz63 I do believe the preferred material would be metal and I did review every post starting with the first. I did take into consideration your point of view regarding the plastic gear vs. a metal one, still this is a risk I'm willing to take. I do understand before I can claim victory this must be put to the test of many roads, landscapes, all types of weather and time. I agree duplicating the gear to the same material is the safest way to go (also working on it). When I did remove the protective cover plate I did not bend or removed the rubber seal, patience is the key in doing the job because it does take a lot of time. I dont recommend for anyone to folllow my foot steps but someone has to step up to the plate and test the metal gear out! (If it can be done;)
 
#141 ·
yagemj, thanks so much for your answers.

I put the front wheels of the X3 on the two plastic ramps I normally use for oil changes, and can see the actuator clearly. However, due to the heat shield, brace, and the exhaust system all being in the way, I am having a hard time opening the four torx bolts. I will try putting the brace down on the passenger side as you recommended. Could you please attach a picture or a URL to the "female torx" socket you bought - what size do I need? I think that'll help a lot. Also, how do you remove the electrical connector...I tried "prying" open the tab, but no success so far...

I did change my transfer case oil yesterday but as expected, that did not fix the light triad issue. However, I feel much better now that there's MUCH cleaner fluid in there.
 
#142 · (Edited)
For the heat shield I removed all the bolts and if I remember correctly I pushed it down a bit and was able to get it out by rotating it to the side a bit and then pull it out. The sockets are called " e torx sockets" they look like normal sockets from the outer case(shell) but have a star patter cut out instead of the normal 6 or 12 point socket. I wish I could remember the sizes but the more I think about it I'm sure the bolts holding the actuator to the transfer case you use the "e torx socket" and the bolts to separate the motor from the actuator you can use a normal torx socket to remove. I'm off tomm and it would only take a second for me to check and get back to you on the sizes.

http://www.amazon.com/gp/aw/d/B000I45Y8Q/ref=aw_d_iv_hi?is=l

As for the clip I honestly don't remember, I must not have had a hard time with it. Maybe once you have it unbolted it will be easier. If the link doesn't work you can google "e torx socket" and it will show them, I'll check the sizes in the am.
 
#143 ·
yagermj, thanks again! This forum and it's members are so helpful!

OK - one (hopefully final) question: to do the 180 deg rotation fix suggested by pburnett: do I need to remove the actuator from the transfer case only, or do I need to remove the motor from the actuator only, or both? Also, do I need to remove the electrical connector on both ends?
 
#144 · (Edited)
Not a problem at all and I'm glad to help , yes you need to remove the actuator from the transfer case ( the four e torx bolts). Once off you need to separate the motor from the actuator(four normal torx bolts). The reason is to be able to rotate the gear you pull the motor off to disengage the metal spline shaft from the gear. This allows the gear to be spun 180 degrees. If you look at the pictures on page 5 you'll see the motor and spline shaft off of the actuator and the actuator. You spin the white wheel/gear to rotate the gear inside. I'll in box you my cell number. I'm headed to breakfast with my wife then I'll get those bolt sizes for you. The wire harness only needs to be unclipped from the actuator also
 
#145 ·
After crawling back under there I noticed a few things the heat shield has to come off or be moved down. This includes the two braces in the center of the truck(10 mm bolts) the e torx bolt size is e 12 to get the actuator off the transfer case and a t 25 to separate the motor from the actuator.
 
#149 ·
I'm sure once the heat shield is out of the way there will be more room to get at it. I think it's just a tab connector( I could be wrong) I think I used a small hook\ pick tool to lift up the tab from the end and pulled it back. Either way without the shield and it unbolted it should be cake.
 
#150 ·
Update plastic gear: Today I've gone to different plastic molding companies and all said the gear is made of nylon and that it would have to be made by an injection mold. Two of them turned me down:thumbdwn: one of them said they can do it:), they told me they would charge me $1.50 per gear out of the same material catch is they would charge me another $12,000.00 to make the mold yyyiiikkkeesss!!!! :yikes: Two more places to go I'll let you guys know how that goes. Metal gear update: still waiting!
 
#153 ·
metal gear

Finaly the gear expert (friend) had some time to view and inspect the nylon gear from the actuator motor. His thoughts were that he had no problem doing the helical gear wich is the one that gets worn out by the metal worm however the top gears would be a problem and unable to duplicate do to not having right equipment. After explaining were gear is from his response was, " maybe its a weak link design to fail to protect other componets in the system". wow! He did lead me to another gear & machine shop and yes it can be done for about 850 bucks! I also did go to diffrent injection molds businesses all with he same response 10k - 13k just for making the mold.:thumbdwn:
 
#156 ·
I bought it from LONESTAR IMPORTS in houston texas, they also have a website. Still I recommend for you to buy a new one, 350 dollar savings and taking a risk might not be the smartest way to go, the only reason I done it was I had already spent 1,700.00 at the dealer:thumbdwn:for replacing crank case vent valve, vent hose, upper middle lower hoses, thrust rod bushing,drivebelts,valve cover gasket(oil leak) and so on, then i needed a break job:tsk: so i took it to a indy shop 500.00 bucks. Then the lights came on!!!! all this happen in the same month so back to dealer, they quoted me at 1,250.00 to replace actuator motor:bang: couldnt afford it anymore.
 
#159 ·
Ok trying to remove the actuator from the car seems pretty complicated. trans crossmember is in the way, or heat shield is in the way.

I am trying to understand that if you just remove the motor, and the gear is inside the gear housing, how do you rotate it?? its seems you have to remove the whole thing, then unbolt motor from the gear housing then rotate the gear?

Thanks in advance guys :)

Frank
 
#160 ·
wyowolf - I had the same experience. I spent 6 hours on trying to remove the actuator yesterday with no success. What is disappointing is that I got three of the four bolts out, as well as both the electrical connectors out. One of the top bolts was just too inaccessible. That transmission brace definitely needs to come out, but it seems it'll bring down a whole bunch of drive train components with it. Ideally, the heat shield would need to removed as well, although I was able to move my hands in there by taking just the two front bolts out and lowering it. Removal of the heat shield will required removal of the exhaust system as well. I had the car's front end on two jack stands and it seems that this job is handled much better with the vehicle on a lift. I had to put everything back together last night since I only have the one car and I needed it for this morning. Besides, I can't think of what else I would do to take the fourth bolt out.

On the e-torx socket, I used size 12, although that seems just a tad bigger than what's needed - not sure if they make a size 11. The set I bought goes straight from size 10 to 12.

Another consideration is that this fix is not an urgent fix since the car runs rather well on 100% RWD, UNLESS you live in one of those states that requires an annual safety inspection. I've been told the car will not pass the safety inspection because the BRAKE and ABS lights are on. What in the world was BMW thinking when they threw the triad of lights for a transfer case actuator malfunction? The brake and ABS systems themselves are fine. It's just that the car can't achieve it's stated dynamic stability control goal completely that comes with the X-drive system. Unless I am missing something, the only light that should come up with this particular malfunction is the 4x4 light. If they needed the yellow 4x4 light to indicate another failure mode, well they could have color coded this one red! This is simply ridiculous and has the unintended consequence of getting the owner to fix the actuator problem to resolve the BRAKE and ABS lights.

Well, I am now leaning towards buying the actuator on ecs tuning and taking it to my indy guy to see how much labor he wants for it. I don't think I want to spend the labor hours just for getting them to rotate it.

Several folks on this forum including yagermj have been so helpful and I feel bad for getting so close and not being able to do it. I guess most of you other folks are more handy than I am.
 
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