[dn.34]

This issue has been driving me crazy, and I am desperate for a solution.

When doing parking lot maneuvers, and turning the wheel full lock, my X3 shudders and bucks like crazy.

2008 BMW X3 with a manual transmission.

Here is the timeline of events:

The car drove perfect until I installed brand new Toyo snow tires on a set of factory wheels. I drove out of the shop and the car was juddering when turning. After a minute or two of making sure the issue wasn't in my head, I thought to undo what I had done. So I pulled back in and put my summer tires back on. Pulled back out and same issue.

I did some research and found people with a similar issue, some people had luck with changing the transfer case fluid. The car has 180,000 miles on it, so this seemed a logical step. I changed the fluid with the ridiculously expensive xdrive transfer case fluid. No change.

I then pulled the transfer case actuator off to check for ware on the plastic gear. It was 95% perfect, but I rotated it and reinstalled just in case. No change.

I acquired a 80,000 mile mostly complete parts car at this time. In order to rule out a differential, or axle issue, I swapped both differentials and all four axles into my car. Unfortunately the parts car did not have the transfer case. No change.

I found several people who had luck with having the entire transfer case replaced under warranty. I was not about to just throw a 1000$ transfer case at the car. I pulled my transfer case and opened it up. I was very careful to document each disassemble step with pictures and notes. Everything inside looked pristine. I have fair experience with a wet clutch like this transfer case uses, and found no issues with the friction plates or the steels. Nothing looked burnt, and everything seemed to be flat. I was unable to find a spec for the thickness of the plates however. The only issue (and I'm not sure if it's an issue) I found was that some of the friction material from the friction disks had collected at the bottom of the channels of the outer clutch hub. Since the issue if the car seemed to be that is is locked into four wheel drive, I figured that maybe enough material was stuck in the grooves, and it was not allowing the clutch pack to spread properly, and was keeping the clutch engaged. I meticulously cleaned out all the material, reassembled and reinstalled the transfer case. I pulled out of the shop hopeful, but no change.

I am not sure why I had not thought of this earlier, but I then crawled under the car and unplugged the transfer case actuator. This obviously disables the actuator, so the clutch pack should be completely relaxed, and disengaged. The car no longer has any torque going to the front diff. Got back in and drove off. Finally sweet relief. Absolutely no shuddering, and on faster sweeping turns the car drove better than before.

I swapped the actuator with a used one, and recalibrated it with Ista+, but still the same shuddering when plugged in, and perfect when unplugged.

The car doesn't throw any codes with the actuator plugged in when scanned with Ista.

This is my understanding of what is going on:

The four wheel drive system is locked on. The clutch pack in the transfer case is fully engaged and is not allowing for the rotational speed differential between the front and back of the car when turning sharply.

Because unplugging the transfer case actuator fixes the issue, and knowing that the "resting state" of the clutch pack is to be disengaged, I believe that this is a control issue. The actuator has to hold the clutch pack engaged against a spring force in order to lock the four wheel drive, so something must be instructing that to happen. I don't believe it's a problem with the actuator itself because that was swapped without change.

Knowing that the car must take steering angle input inorder to determine when the clutch pack and four wheel drive should be disengaged, I recalibrated the steering angle sensor with Ista. This was successful, and I could see a live readout from the sensor when I turned the wheel. Seems to be working properly.

At this point I do not know what else to try. I'm a engineering student, and do not have funds to just throw parts at it willy nilly. Nor is it my style to do so.

If anyone has any input or suggestions as to what could be going on, it would greatly appreciated. I go to school at Michigan Tech where it is extremely snowing. Its not an issue to drive the car with the actuator unplugged, and in 2wd during the summer, but I need 4wd when at school in the winter. The car is drivable with the shuddering issue but it makes my mechanical sympathy scream.

Please help.

[englishtom1596]

It sounds like you've pretty much isolated it to the actuator. When your actuator is getting powered (plugged in) its not going to the commanded positions. I know the actuator is like $300 but I don't see it being anything else since you've cleared everything else mechanical and software related

[goldaxx]

I currently have the same problem. Removed the actuator nd checked the plastic gear. Everything perfect and in working order. When I disconnect the transfercase everything runs smooth and no shuddering. When connected the shuddering reappears Transfercase fluid has been changed twice in the last 3 years (last time when I changed the clutch only 2000km ago) also the steering angle sensor has been swapped. Still no change I heard that difference in tire pressure and/or faulty wheelsensors could be a cause. That is what I will be checking next.

Curious if you finally found out what the problem is?

Best of luck anyway

Originally Posted by dn.34

This issue has been driving me crazy, and I am desperate for a solution.

When doing parking lot maneuvers, and turning the wheel full lock, my X3 shudders and bucks like crazy.

2008 BMW X3 with a manual transmission.

Here is the timeline of events:

The car drove perfect until I installed brand new Toyo snow tires on a set of factory wheels. I drove out of the shop and the car was juddering when turning. After a minute or two of making sure the issue wasn't in my head, I thought to undo what I had done. So I pulled back in and put my summer tires back on. Pulled back out and same issue.

I did some research and found people with a similar issue, some people had luck with changing the transfer case fluid. The car has 180,000 miles on it, so this seemed a logical step. I changed the fluid with the ridiculously expensive xdrive transfer case fluid. No change.

I then pulled the transfer case actuator off to check for ware on the plastic gear. It was 95% perfect, but I rotated it and reinstalled just in case. No change.

I acquired a 80,000 mile mostly complete parts car at this time. In order to rule out a differential, or axle issue, I swapped both differentials and all four axles into my car. Unfortunately the parts car did not have the transfer case. No change.

I found several people who had luck with having the entire transfer case replaced under warranty. I was not about to just throw a 1000$ transfer case at the car. I pulled my transfer case and opened it up. I was very careful to document each disassemble step with pictures and notes. Everything inside looked pristine. I have fair experience with a wet clutch like this transfer case uses, and found no issues with the friction plates or the steels. Nothing looked burnt, and everything seemed to be flat. I was unable to find a spec for the thickness of the plates however. The only issue (and I'm not sure if it's an issue) I found was that some of the friction material from the friction disks had collected at the bottom of the channels of the outer clutch hub. Since the issue if the car seemed to be that is is locked into four wheel drive, I figured that maybe enough material was stuck in the grooves, and it was not allowing the clutch pack to spread properly, and was keeping the clutch engaged. I meticulously cleaned out all the material, reassembled and reinstalled the transfer case. I pulled out of the shop hopeful, but no change.

I am not sure why I had not thought of this earlier, but I then crawled under the car and unplugged the transfer case actuator. This obviously disables the actuator, so the clutch pack should be completely relaxed, and disengaged. The car no longer has any torque going to the front diff. Got back in and drove off. Finally sweet relief. Absolutely no shuddering, and on faster sweeping turns the car drove better than before.

I swapped the actuator with a used one, and recalibrated it with Ista+, but still the same shuddering when plugged in, and perfect when unplugged.

The car doesn't throw any codes with the actuator plugged in when scanned with Ista.

This is my understanding of what is going on:

The four wheel drive system is locked on. The clutch pack in the transfer case is fully engaged and is not allowing for the rotational speed differential between the front and back of the car when turning sharply.

Because unplugging the transfer case actuator fixes the issue, and knowing that the "resting state" of the clutch pack is to be disengaged, I believe that this is a control issue. The actuator has to hold the clutch pack engaged against a spring force in order to lock the four wheel drive, so something must be instructing that to happen. I don't believe it's a problem with the actuator itself because that was swapped without change.

Knowing that the car must take steering angle input inorder to determine when the clutch pack and four wheel drive should be disengaged, I recalibrated the steering angle sensor with Ista. This was successful, and I could see a live readout from the sensor when I turned the wheel. Seems to be working properly.

At this point I do not know what else to try. I'm a engineering student, and do not have funds to just throw parts at it willy nilly. Nor is it my style to do so.

If anyone has any input or suggestions as to what could be going on, it would greatly appreciated. I go to school at Michigan Tech where it is extremely snowing. Its not an issue to drive the car with the actuator unplugged, and in 2wd during the summer, but I need 4wd when at school in the winter. The car is drivable with the shuddering issue but it makes my mechanical sympathy scream.

Please help.

[booney1960]

Hi, new to the forum.
We had exactly the problem you describe which was eventually diagnosed as two ABS sensors faulty. Replaced all 4 as a matter of course and car drove perfect again.
Regards
Booney