Transfer Case Actuator potential free fix!

Originally Posted by yagermj

Hey guys (anyone having cross member issues) you do need to move it. I unbolted the passenger two bolts of the cross member after I supported it with a floor jack. Then lowered the cross member about 3/4 to 1 inch to gain access to the actuators top bolt. Hope this helps

This may be a dumb question, but is the transfer case resting on the cross member? You say you supported it with a floor jack, then unbolted it before finally lowering it 1 inch. Could I just remove it to get to the actuator or that would be unwise? Why?

Thanks

The cross member supports the transfer case. The cross member could be removed but that would mean another type of support for the transfer case or a complete removal of it. The exhaust is still there and in the way of the removal of the brace also. It is much more work to me to remove the brace alltogher and not needed. I have ordered a new actuator and when it arrives will do a write up with pictures. Keep in mind this is just how I did it and I'm sure there are other ways. In total it took me longer to figure out how to take it all apart then to do the fix. This time I'm sure I can remove and replace the actuator put it all back together in two hrs time.

Yesterday I had the misfortune of viewing the 3 lights on my dash indicating a potential problem with my transfer case actuatorf. After do my due diligence on various BMW blogs I settled into the fact that I would soon be visiting Hans at my local BMW dealer, but to my surprise this morning, the lights went out and the car stopped struggling with its rear end.

Does anyone out there think that this intermittent problem could be caused by a corroded conector.? One would logicaly think that the transfer case actuator is working or not working, right. ??

Any comments would be appreciated.

Norm...

norm w - I would not automatically assume you have the same worn gear problem which is the main topic of discussion in this thread. As far as electronics, there are two related components on an X3. P/N 2760759988 is the control unit for the transfer case, and P/N 27107557345 is a resistor which on the realoem.com diagram seems to reside on the actuator end.

BTW, I talked to one of the BMW indie techs in this area and he said he's swapped two X3 actuators. Both cars had uneven tire tread depths. I have to admit, I have that issue as well...three older tires, and one newer tire. I wonder if fractions of a mm can cause so much stress on the actuator. Wouldn't uneven inflation pressures amount to similar differences in the wheels' overall diameters? When I mentioned to him this may very well be a design flaw given the number of folks experiencing the problem, he pretty adamantly refuted. Regardless, one would expect this component not to be so sensitive but a bit more robust.

Finally, after a 10 hour marathon starting Friday evening, I was able to carry out the 180 deg rotation. Lights are gone - have driven 25 miles since the fix.

I'm curious what is the most miles anyone has driven since this fix without a subsequent issue. 25K miles? 50k?

I took some pictures of the alleged culprit gear. Interestingly, at least to me, it looked very similar all the way around (360 deg.). That said, the issue does seem to be fixed, even if temporarily.

This job is all about underneath access and tools. It is the most difficult thing I've done on this truck. If you don't have access to a lift, please be careful not to strain your shoulders or neck. If the fix lasts for at least 50K miles, it is certainly worth the trouble.

Another related observation and question for the community...

Now that the 4x4 system is working again on my X3, I have resumed noticing a parking feature which was notably absent during the few weeks the 4x4 system was out (truck was on 100% rwd).

When I come to a stop and shift the transmission to "P," there is usually a "thud" that comes from the drivetrain, accompanied by the slightest nudge of vehicle to the rear. It is as if the transfer case actuator gear adjusts itself by a tooth when the vehicle comes to a stop and is parked.

Anyone else notice this? Is this normal? Is this the cause of the gear wear? What causes this? Is this related to unequal tire tread depth?

Great thread, appreciate the fix for a common issue. Does anyone have instructions for removal (where it is under the car, step by step how to remove it)? It seems some are able to get it right off of the car while others are having a difficult time. Thanks!

Hello everyone...need some help.

2007 X3...accelerates fine...no sound at 50-55 mph and release the accelerator have a roaring sound, not actually a vibration but a roar, no clunking or big sounds, just a roar. Car will not do it at any other speeds, go 70-75 and release accelerator--no sounds....go 40 mph and release accelerator---no sounds...Anyone got an answer...car has 69000 miles on it.

Thanks

Originally Posted by pburnett

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/sho...6&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 !!!) 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!

Thank you sooooo much for the post.
I followed the instructions and it is now working.
However like someone posted I am not sure if it will work once 4X4 is asked for, but the 4X4 light went out. In addition I made sure to clean everything carefully and relube.
Someone was wondering if the black gear goes bad because the load is too high.
I found 3 cracks in the white nylon gear as well. This will cause it to expand, in turn causing slippage and perhaps make it go stuck, but for now it is fine.
I could perhaps have tied some metal wire around the white gear hold it together.

Lars

In my former post I said that I noticed 3 cracks on the bottom of the white nylon gear.
I decided to take it apart again and reinforce the gear with a sleeve. I found a 1 1/4 inch brass drain pipe that fit exactly. Not only is it very thin so that it doesn't interfere, but it is just small enough so that it tightens up the cracks in the gear. I decided to reinforce the top of the gear as well that connects to the transfer case.
I feel that the nylon gear in the cause of the problem. When the black gear tries to turn it, it expands enough for the teeth to get stuck.
I have attached pictures to explain.

Hope this helps.

Lars

I found this site and I really thank you all for the input. My 08 X3 started making the clicking sound Saturday morning, took it to a local shop where I live (not BMW). They said it was coming from the transfer case area. Made an appointment at the BMW dealer to confirm the noise. I get no dash lights so I hope that it is the same problem or less that you all have said. Great site and a very awesome tread about this problem.

Originally Posted by desertviking

In my former post I said that I noticed 3 cracks on the bottom of the white nylon gear.
I decided to take it apart again and reinforce the gear with a sleeve. I found a 1 1/4 inch brass drain pipe that fit exactly. Not only is it very thin so that it doesn't interfere, but it is just small enough so that it tightens up the cracks in the gear. I decided to reinforce the top of the gear as well that connects to the transfer case.
I feel that the nylon gear in the cause of the problem. When the black gear tries to turn it, it expands enough for the teeth to get stuck.
I have attached pictures to explain.

Hope this helps.

Lars

Nice! Thanks for the update and pictures.

Originally Posted by jpapa

It seems some are able to get it right off of the car while others are having a difficult time.

This was a good question that has me wondering as well. Any thoughts?

Is it model year dependent, transmission type or something else?

Originally Posted by desertviking

In my former post I said that I noticed 3 cracks on the bottom of the white nylon gear.
I decided to take it apart again and reinforce the gear with a sleeve. I found a 1 1/4 inch brass drain pipe that fit exactly. Not only is it very thin so that it doesn't interfere, but it is just small enough so that it tightens up the cracks in the gear. I decided to reinforce the top of the gear as well that connects to the transfer case.
I feel that the nylon gear in the cause of the problem. When the black gear tries to turn it, it expands enough for the teeth to get stuck.
I have attached pictures to explain.

Hope this helps.

Lars

These photos are interesting in that it shows that the problem with the gear is poor molding and poor mold design. If you look closely, you will see that the 3 cracks are halfway between the 3 "bumps" on the top surface of the gear. These are where the plastic enters the mold. If the molding conditions are not quite right, when the flow from one gate runs into the flow from one of the other gates, the material does not "knit" properly and a weak area if formed. These are the areas that you now see cracking.

Got a new one today for 670.00 out the door and dealer will put it in for 117.00.

Originally Posted by dannyy06

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

I email the guy and he won't even sell the gear. I thought hat was weird.

Conclusion / Resolution
Okay here is the bottom line:
The car is fixed using the workaround in this link: http://www.bimmerfest.com/forums/sho...d.php?t=566880
Cost:
Mechanic replacing transfer Oil that BMW says for life $93.
BMW diagnostics to make sure it is the Transfer Case that is damaged: $135
1 Hour labor for a friend mechanic who agreed to do the workaround: $65.00
Total $293 vs. $1700.00 BMW estimate
You can save all of this money if you have the courage and patience to do it all. i would have done it if i had another car!
You definitely need the lift or the job will take half a day ..
you definitely need to take the actuator out because other wise its very hard to see the damaged area and 180 degrees is not holy
look into the actuator motor and you will be able to see the damage rotate until you see the damaged area gone
Drove it 100 miles since the fix and it rained hard .. no problem .. flies like new ..
Thanks PBURNETT!!!

Well....
I am now back to the original issue which is: When I start up the car, I get a squealing sound like a belt slipping. When it began, I would quickly shut off the engine, turn it back on and the sound would be gone and the car would operate normally. Few days later when it happened I decided to leave the car running, open the hood and look at the serpentine belt. The sound didn't seem to come from there however. I then got back in the car, turned it off and on again. THis time however the 4X4 light was on. When I backed it up carefully it stopped by itself after say 20 yards. I then tried going forwards with the same results. Given the car a little power I heard some bad sounds from underneath. This is when I stopped and eventually repaired the actuator.
Now I am back to the intermittent squeal. I am afraid that the transfer case is bad somehow. I know there is a chain in there, which I wouldn't think could produce a squealing sound.
I am perplexed!!!!

Originally Posted by 3gunshooter

Got a new one today for 670.00 out the door and dealer will put it in for 117.00.

Where did you the new actuator for $670? That is a pretty good price, better than the 20% off you can get at getbmwparts.com.

Also, which BMW dealer is willing to put it in for $117? That is an excellent price. Here in the DC area they would have charged at least 4x that price.

Make sure they re-program the car (the new actuator needs to "adapt" to the car).

Originally Posted by nrigroom

Where did you the new actuator for $670? That is a pretty good price, better than the 20% off you can get at getbmwparts.com.

Also, which BMW dealer is willing to put it in for $117? That is an excellent price. Here in the DC area they would have charged at least 4x that price.

Make sure they re-program the car (the new actuator needs to "adapt" to the car).

I live in Indiana, The dealers here have an online store you can get them from. They said it was for the do it your self type. But if you buy it at the dealer it was 940.00(I know, does not make sense) Basney BMW in South Bend is doing the labor that was the quoted price. They do really good work, the guy had it off in about 20 min. to confirm that's what it was and put it back in and I was out in less than a hour. I got the part and get the new one in on Friday. I feel lucky

Originally Posted by 3gunshooter

I live in Indiana, The dealers here have an online store you can get them from. They said it was for the do it your self type. But if you buy it at the dealer it was 940.00(I know, does not make sense) Basney BMW in South Bend is doing the labor that was the quoted price. They do really good work, the guy had it off in about 20 min. to confirm that's what it was and put it back in and I was out in less than a hour. I got the part and get the new one in on Friday. I feel lucky

Good for you! You'll probably need to eventually replace it anyway.

This is probably the most useful thread on the X3. However, I wish eventually other more knowledgable subiscribers can answer the following questions about the actuator:

1. Why does a 180 deg fix the problem? Does the worn gear in question NEVER rotate more than a few degrees relative to it's set point? What does the rotation of this gear while driving actually accomplish? Vary the engine torque between the rear and front axles?
2. Has anyone obtained > 25K miles after the rotation? One subscriber had to replace the actuator within just a few months of rotation.
3. When you hit the 4x4 button on the dash, is this actuator completely disengaged from the driveline? Meaning, no load on the worn gear in question?

One question for you: On http://www.basneypartsonline.com, the price I see is $900.31 - do they only give you the online store price if you actually physically walk-in? I am wondering if there's a way I can use their excellent prices for my future needs

Well, I'll give it a crack...

Originally Posted by nrigroom

1. Why does a 180 deg fix the problem? Does the worn gear in question NEVER rotate more than a few degrees relative to it's set point? What does the rotation of this gear while driving actually accomplish? Vary the engine torque between the rear and front axles?

That was a topic of discussion early on in this thread. Apparently, the gear never rotates more than 180 degrees to accomplish its function, which as you surmised, is to distribute torque between the front and rear axles. Somewhere on the forum (could even be within this thread) a short tutorial video was posted about xDrive; the transfer case operation was quickly highlighted.

Originally Posted by nrigroom

2. Has anyone obtained > 25K miles after the rotation? One subscriber had to replace the actuator within just a few months of rotation.

I don't think anyone's had this short-cut repair implemented for long enough.

Originally Posted by nrigroom

3. When you hit the 4x4 button on the dash, is this actuator completely disengaged from the driveline? Meaning, no load on the worn gear in question?

I don't believe anything (short of a malfunction or failure of the transfer case gear) can fully disengage the xDrive system; it's a full-time all-wheel drive system.

I don't believe anything (short of a malfunction or failure of the transfer case gear) can fully disengage the xDrive system; it's a full-time all-wheel drive system.

i think it is a full time on demand all wheel drive .. controlled by a computer ..
that's why you get the hesitation on take off uphill .. triggers the 3 lights ... or
when road is slippery .. that also turns the 3 lights on
they are not on all the time ...
only when awd is kicking in ..
just a thought ...

Originally Posted by X32006

i think it is a full time on demand all wheel drive .. controlled by a computer ..
that's why you get the hesitation on take off uphill .. triggers the 3 lights ... or
when road is slippery .. that also turns the 3 lights on
they are not on all the time ...
only when awd is kicking in ..
just a thought ...

My understanding is that the xDrive system is active at all times under normal operating conditions. The system is RWD-biased (40%/60% split between the F/R axles) but fully variable between nearly 100% FWD or 100% RWD depending on the traction conditions; there are some operating conditions (independent of traction conditions) where it operates entirely in RWD.

Originally Posted by timfitz63

Well, I'll give it a crack...
I don't believe anything (short of a malfunction or failure of the transfer case gear) can fully disengage the xDrive system; it's a full-time all-wheel drive system.

Understand, but my question is with reference to the actuator only. The xDrive system senses vehicle states such as yaw rate, steering angle, wheel rotation speed, and responds by actuating selective braking, torque distribution between rear-and-front axle, and engine throttle override.

That is the xDrive system which, as you noted, can't be overridden. However, it seems that the sole purpose of the transfer case actuator is to allocate torque split between the front and rear axles. It does not involve itself either in braking or in throttle input reduction.

Now, my question is when you toggle the 4x4 button on the dash to it's off position, is the subject actuator not in play? One would logically conclude this based upon the emblem and dash light display assigned to this button. I do understand that other components of the xDrive, viz., selective braking and throttle reduction are still active. This is the only conclusion which makes sense to me, but I am not sure and therefore picking on others' brains.

What I am leading to is this: IF this conclusion is correct, one can get a lot more mileage out of the rotated actuator by keeping the 4x4 button off. I think what'll happen in such a situation is that the vehicle will be RWD, but all other components of the xDrive system will still be active. Of course, keeping the button permanently off defeats the whole purpose of buying a 4x4 vehicle in the first place, but at least I want to know how the system works, and I want to use it as I please. Certainly it is recommended to drive with the system on in rainy or snowy conditions with the exceptions as noted by BMW.

Am I right? Way off?