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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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#364 ·
Hello Supercourse

I was cheking in the car but i dont find other black case than this in the photos
this is located between the battery and the compartiment where is located the silver one

so please let me know if are any other and where is it

Thank you sorry im trying to fix this
but i see my actuator is not working well i have the 4X4 turned on and many people tell me that i have to change the servomotor
but i already change the gear
i hope i can fix this
i see that other person have this problem before and he say he change the sensor of the actuator
but im not sure if this sensor is the same resistor on this page

www.bmwpartsweb.com/Part-Numb..._E095124A.aspx&jsonp=vglnk_jsonp_13849628979366

so im trying to fix
thank you friend
 

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#366 ·
So the black plastic in front of the silver box is just a wiring connector? Not sure where Fatzio found a fusible link but he implies it was in that area.

Maybe in-line with the wiring going into that black plastic connector?

Not sure StickyDonkey was talking about replacing the resistor that you linked to. That is on the actuator and gives the code 54C8 when faulty.

This is for a X5 but same box: http://www.xoutpost.com/bmw-sav-forums/x5-e53-forum/82294-code-54c8-vtg-classification-resistor.html

The code for "oil wear" in the VTG (transfer case) is 54C6 and I presume that resistor is involved in resetting the adaption values when new fluid is put in.

Possibly he was referring to the resistor as a sensor because that is its purpose - but I don't see that you need to change it without knowing you have that code stored.

Best to keep looking for that fusible link to check it.
 

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#368 ·
Hi Recasal
Apologies for not being back in touch but i've been away for a few days. The fuse i was on about is in the wiring that goes to the control unit, but it is not (on my car) located in the battery compartment, it is under the panel that is in front of the battery compartment. There are three black plastic clips that hold the panel (boot floor) down, remove these lift the panel and it should be there. If you can't find it let me know and i will take some pictures.
Good luck
 
#371 ·
Hi Racasal
I can't attach the pictures i.ve took for some reason, if you send me your e mail address i will send them to you. Of your pictures the bosch unit looks like mine but mine has a in line fuse to it, perhaps yours has a fuse in a fuse box in the rear compartment?
 
#372 ·
Thinking here may be the more suitable thread.

My transfer gear box actuator gear finally broke down last week. The car has only done 4 years 46K kms mainly start stop city driving. Ordered aplastic gear and spent 4 hours to install it. All 4 warning lights gone afterwards.

I've noticed the 4 wheel drive light is no longer flashing when driving through some leaves and the tire is slipped slightly, don't know whether is normal.

The second thing I've noticed is the quality of this plastic gear. The OEM gear has PA66 CF30 printed on it, that means using Nylon 66 with 30% carbon fibre. The replacement gears available in the market are various. Some are white nylon with glass fibre, some are PA66 GF30---black Nylon with fibre glass, some are the same as OEM. It's interesting Odometer Gears claims their ones are made of high temperature Nylon (HTN) with carbon fibre. I am not sure what type of high temperature Nylon they are using, RTP4485, PA6T or PA9T? This will make sense if this gear is truly made of HTN as the PA66 can only continuous working on 110 C with melting temperature 260 C and PA9T has melting temperature 305 C which will bring the operating temperature up 30 degrees. The 30 degree increase will make a big difference to the gear's reliability considering the temperature near the transfer box can be high as it's close to the exhaust.

Another thing I can think of is the gear is made of carbon fibre so overall it's strong but against the abrasion of the worm gear, it may not be. In the good old day, metal gears have to be chemically heat treated to make the skin hard to against the abrasion but the core remain soft so it won't be brittle. Bronze gear may be harder but may wear out the worm gear quicker. So it's a hard balance to select the right material. For the moment I can see the best thing we can do is to pick a better Nylon carbon fibre gear and make sure the lubricant is at its best--- I used Superlube synthetic grease with PTFE.

Does anyone know what HTN the Odometer Gears gear is made of?
 
#376 · (Edited)
It's me again looking for some help from you guys. I just pulled off the actuator several times, with the actuator out of the transfer and the power and sensor connector attached I started the car and the actuator make a 300~320 degrees rotation on the gear. Installed the actuator last time and now when I just start the car the 4x4 light is on (not with the ABS and Brake like before) and when I start driving the car, the wheels appears to be getting some random power specially cornering. Do I need to change the complete transfer case? is this a sensor/resistor failure? Thanks for your help.
 
#377 ·
BMW-X3,

Would that be the reason the transfer case needing some sort of calibration/resetting/reprogramming? This has been discussed in several other threads. My own X3 won't flash the 4X4 light on slippery surface after replacing the actuator gear. I'm thinking of getting some programming gear to look into this (DIS program?)

I've also received feedback from a plastic gear maker that the BMW programs their transfer case to act more aggressively/sensitively and it's reported it wears out the actuator 500 to 1 more often, comparing to the exact M-Benz transfer case.
 
#378 ·
As I understand it, there are 2 things that can be programmed with the X3's transfer case:

1. The fluid wear value code (54C6), if triggered, can be turned off after replacing the fluid. This is just a simple deletion of a stored code in the transfer case control module (VTG).

2. The adaptions can be reset after replacing the fluid, irrespective of whether the fluid wear value code was set or not. This requires the BMW computer to activate the VTG and make an adjustment to how the clutch plates operate.

These two can be independent actions, or they can be called for simultaneously.

Then my understanding gets fuzzy. I think the resistor is just used in the algorithm that estimates when the fluid needs replacing and does not involve any xDrive components.

The adaptions are presumably linked to xDrive and essentially re-calibrate the pressure applied to the clutch plates according to the viscous and/or other properties of the fluid.

If the adaptions are not reset after changing fluid, the algorithm to detect when the new fluid has exhausted its useful life will not work properly.

How DSC and DTC is affected by the new fluid I am not sure. If the actuator resistor somehow allows for variations in clutch pack performance as the plates wear, I don't see how new fluid affects that.

I can sort of see that replacing the transfer case with a new one and bolting on the old actuator might need some re-programming to get everything working properly.

Or, putting a new actuator on an old transfer case could work fine or it might be best to re-do the adaptions.
 
#380 ·
I meant to mention that I can't see why replacing just the gear wheel would require any further action.

Should be no different than rotating it 180 degs. in terms of what VTG knows.

Replacing the fluid or the resistor I can see having a meaningful impact, but as long as the gear wheel is the same size and configuration, how could it?

As early models of the X5 had a pre-cursor to xDrive, some differences in experience compared to the X3 after component replacement are understandable.

But do we have a pattern of X3 owners experiencing no change in symptoms, or new problems, after replacing the gear wheel?

The first few who reported back seemed to have no problems and didn't go to the dealer for re-programming.
 
#381 ·
Hi guys, I just scanned my X3 (after replace the actuator gear and keeping 4x4 warning light on) and the error codes are:
54C6 Oil wear
5462 Servomotor or coupling force too high
5F3A Transfercase: malfunction.

The BMW Technician that scanned the X3 suggested replace the actuator motor with a new one. I have tested the actuator motor powering with 12V pins 1 and 8 and it spin with out any problem, maybe the damage is on the internal board?
 
#382 · (Edited)
BMW-X3:

The new information is very helpful.

54C6, does it mean the oild need to be changed? From all the other transfer case discussion seems to conclude the oil gets dirty very easily and contains metal particles.
5462, I am still unsure if this is to do with the alignment/programming/adaption. As I understand when the car is going normally, no slip, the actuator should be in a position which makes the front/ rear load 45/55. When slipping, the actuator turns and the ratio changes. The observing points seem to be the starting and stopping, i.e. when starting the car, the actuator will turn the clutch to a certain front/rear ration and when turning off the engine, the actuator will turn the clutch back to its stop position. That's why when the gear fails and the engine is turned off, you can hear the clicking noise from the actuator as it is trying to turn the clutch back to a stop state. Logically, if we know which direction the actuator truns, we can always turn the gear box shaft which couples to the actuator fully the right way when the engine is off and then put the acuator back and try it.

Has the BMW guy told you if fitting an actuator requires an alignment?

I have looked at the motor before but forgot to check the pins. The sensor seems to be a speed pickup rather than a position sensor so the resistor can be a shunt resistor which can alter the torque of the motor. This can be verified by checking the terminals of the resistor, one should go to the power positive, the other one should go to a coil (shunt field) of the motor. The other side of the coil should go to the power negative (or return).

Once I've got access to a BMW programmer, I should find out more of this.
 
#383 ·
Actuator reposition no success, transfer case oil level low?

I have followed this thread and rotated the actuator gear. I started with a blown front diff when I left the repair shop with a recon front diff. The three lights of terror came on. Found this thread removed the actuator, rotated 120deg. The lights stayed of when started then came on moments later. I pulled the actuator and rotated gear 180 deg from original position. The gear did not look to be badly worn as shown in some posts. Now I have intermittent brake and ABS light to go with constant 4x4 light.

I have changed the transfer case oil as well and had the computer reset by service tech. Still have three lights of terror.

As it is intermittent, always 4x4 sometimes brake and ABS is it possible that the transfer case oil level is low, causing transfer case 4x4 light thus effecting the brake ABS?

Being an ex aircraft mechanic I love the Bimmer for its simplicity of construction and logical remove and install design (IMO) and these posts have saved me thousand on my X5, great car and able to be repaired by mechanically minded people.
 

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#384 ·
5 min level check ???

gotta have the beasty level first ....then ......crawl under with a 17 mm ....or whatever and pop the trans case level plug ....does it weep out smelly like cat urine fresh BMW oil or is it low ?????

also ....the composite gear does not have to be totally spent/chewed up to fail.....it's a worm/wheel arrangement that can miss/slip when mesh/gear tolerance is poor

also you can insert a strong nylon tooth brush style handle and feel for chain tension....you need next to no slop....DO NOT DROP ANYTHING IN THE CASE !

the geek site had the gear for ~90 ish US $$$$$
 
#387 ·
gotta have the beasty level first ....then ......crawl under with a 17 mm ....or whatever and pop the trans case level plug ....does it weep out smelly like cat urine fresh BMW oil or is it low ?????

also ....the composite gear does not have to be totally spent/chewed up to fail.....it's a worm/wheel arrangement that can miss/slip when mesh/gear tolerance is poor

also you can insert a strong nylon tooth brush style handle and feel for chain tension....you need next to no slop....DO NOT DROP ANYTHING IN THE CASE !

the geek site had the gear for ~90 ish US $$$$$
I will check the level again, when I filled it I used the spill/overflow method, any idea what volume of oil is required?

does anyone else have issues with intermittant lights 4X4 plus brake and ABS??

My next stop is the tansfer case control fuse mentioned earlier in the thread.

the joys of motoring.....Ahhh
 
#389 ·
also ....a dead giveaway for a slipping gear is the machine gun ratter tat tat in this video .....do you have this sound ??????

there is no audible clicking or chatter.

I do have a really bad history with Mr Murphy, when the front diff exploded is it possible that there was some sensor damage in the transfer case?

the 4x4 light only started after the diff fail?
 
#388 · (Edited)
helpful vids

the case etc ....also remember .....nearly every case on all 4 wheel drives derives from the old AMC/Jeep DNA ....don't let anyone spook you about what's in them.....around one litre of the BMW spec oil will do it plus or minus a few shot glasses !

http://www.bimmerfest.com/forums/showthread.php?p=8057183&posted=1#post8057183

how to check fill etc



also ....when actuator motor was apart what did the commutator/brushes end of the motor look like/act like .....brushes in good shape /free/ long enough???? .....commutator clean/no pits just like checking an old starter motor ......some judicious fine emery cloth on the com will polish it good

also .....plug male and female contacts clean ?????....use a smudge of dielectric grease on them ??????
 
#391 ·
the case etc ....also remember .....nearly every case on all 4 wheel drives derives from the old AMC/Jeep DNA ....don't let anyone spook you about what's in them.....around one litre of the BMW spec oil will do it plus or minus a few shot glasses !

also ....when actuator motor was apart what did the commutator/brushes end of the motor look like/act like .....brushes in good shape /free/ long enough???? .....commutator clean/no pits just like checking an old starter motor ......some judicious fine emery cloth on the com will polish it good

also .....plug male and female contacts clean ?????....use a smudge of dielectric grease on them ??????
I will pull the actuator again and take a bit more notice of the actuator parts. pluggs were clean, and I used water dispersal fluid on reassembly.

Thanks
 
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