[Bebbetufs]

On my car I have a juddering and sometimes some slight hesitation under acceleration. This makes me think the transfer case needs a rebuild. But, then I also have wheels crabbing, skipping/dragging in full-lock turns.

The crabbing seems to indicate either a stiff front diff or that the transfer case has trouble releasing the pressure on the clutch plate.

As far as I can tell the transfer case clutch is naturally open and the actuator applies torque to close it. This would lead me to believe that the juddering commonly reported from a worn transfer box is clutch slippage, as wear would likely lead to the actuator not applying enough clamping force on the clutch pack.

However, if the clutch is naturally open I don't see why wear would lead to wind-up in the drive line and wheels skipping/dragging, nor why changing fluid would help. Have I misunderstood how the clutch works, or does this indicate I have a bad front diff?

Can one unplug a fuse to disable the transfer case actuator, or do I need to pull the plug?

[deyrag]

change your transfer case fluid, will most likely fix your issue

[thetyrant]

There is a fuse you can pull to disable the transfer case and put car into rwd only, i cant remember from top of my head but its on here somewhere, as above if the transfer case oil hasnt been changed get that done as its very common to cause both the issues you have.

Also as a first step check the tyres are matching in brand, size and tread depth, too much mismatch and that causes these issues as the transfer has to then try and take up the difference.

Front diff issues seem rare so unlikley imo

EDIT - to add it was fuse 37 on my car to disable transfer/Vtg

[Bebbetufs]

Thanks. The oil has been changed.

I found that both f37 and f66 are VTG related. Is it enough to pull f37 on this generation x3?

Is the tyre skipping VTG related or geometry related? It snowed yesterday so I could study the tracks. The outside front tyre skips/pops inward by up to 15 mm. This happens when going in reverse, not sure in what direction it pops when going forward.. This is at full lock.

[thetyrant]

Ok thats good if transfer oil has been changed, did you also have the VTG calibration done? also any error codes showing ?

I found removing F37 was enough to disable the VTG on my car and identify i had issues in that area, basically i had strange noise from drivetrain and with fuse 37 removed noise it was not there, after changing oil, re-calibrating VTG and other checks i removed the VTG to inspect rebuild as suspected internal issues, upon removal i found the transfer to front diff propshaft UJ was partially seized, replaced the prop and everything was ok again.

[Bebbetufs]

The oil was changed by the dealer. I assume they recalibrated, but you never know....

What part of the prop shaft was frozen? Was it the universal joint? EDIT: didn't catch the abbreviation. Thanks.

[Bebbetufs]

Is it likely that the crabbing is due to the transfer case?
EDIT: I found a phone tool called xTratool. It disables and enbles X-drive for $1.
There was no difference to the crabbing. I have not yet changed to winter-tires so it is very pronounced now with wet snow on the ground. I couldn't go for a proper test drive to check for shuddering under acceleration/turns when the transfer box is warm.

Hopefully it will be warmer tomorrow so I can test drive it with 4x4 disabled.

[Wgosma]

Originally Posted by Bebbetufs

Is it likely that the crabbing is due to the transfer case?
EDIT: I found a phone tool called xTratool. It disables and enbles X-drive for $1.
There was no difference to the crabbing. I have not yet changed to winter-tires so it is very pronounced now with wet snow on the ground. I couldn't go for a proper test drive to check for shuddering under acceleration/turns when the transfer box is warm.

Hopefully it will be warmer tomorrow so I can test drive it with 4x4 disabled.

I think certainly possible; I had some relatively minor 'crabbing' / 'jerking' with the car at VERY SLOW speeds...pulling into the driveway. Car had 70K miles on the clock- after getting the tranny and transfer case fluids changed, and shop 'reset' the transfer case- problem disappeared.

[Bebbetufs]

Thanks. I guess the only way to find out is to disassemble the transfer case. It seems a bit unlikely it will help though, since disabling the transfer case made no difference to the tyre slipping.

[mwat]

Originally Posted by Bebbetufs

Thanks. I guess the only way to find out is to disassemble the transfer case. It seems a bit unlikely it will help though, since disabling the transfer case made no difference to the tyre slipping.

According to the master tech I consulted when I thought I had TC issue it's blatantly obvious when it's toast. Obvious when you're driving, metal shavings in the fluid etc.

Just what I was told.

[Bebbetufs]

I did a long test drive yesterday.
Disabling the transfer case made no difference.
I still have outside tire skipping and driveline vibrations which are speed related.

Suspecting front diff. I'm going to drain the oil to check for metal specs.