Rear Driveshaft failure and Replacement

[jfandl]

I've got a 2014 x5 F15 with a failed rear driveshaft. It spewed black grease out the back where it connects to the pinion and has a grinding sound when you turn by hand so it's clearly wasted.

To anyone who has removed or replaced the rear driveshaft that has the single 50mm nut, did you require any kind of special locking plate or device to remove the nut? I saw the FCP euro video which he says you really need the $350 mounting plate to secure the driveshaft from turning at the center support area, but I cannot find anyone else who used this plate for removal.

Can i keep the driveshaft connected to the transfer case and then simply remove the nut from the rear (clockwise, I know)? Is the parking paw strong enough to hold it without damage? I understand it's torqued to 100Nm but has some loctite making it harder to remove.

[E90convert]

Originally Posted by jfandl

I've got a 2014 x5 F15 with a failed rear driveshaft. It spewed black grease out the back where it connects to the pinion and has a grinding sound when you turn by hand so it's clearly wasted.

To anyone who has removed or replaced the rear driveshaft that has the single 50mm nut, did you require any kind of special locking plate or device to remove the nut? I saw the FCP euro video which he says you really need the $350 mounting plate to secure the driveshaft from turning at the center support area, but I cannot find anyone else who used this plate for removal.

Can i keep the driveshaft connected to the transfer case and then simply remove the nut from the rear (clockwise, I know)? Is the parking paw strong enough to hold it without damage? I understand it's torqued to 100Nm but has some loctite making it harder to remove.

Can you apply the parking brake so the torque gets reacted through the brake instead of the parking pawl? And if all else fails, I suspect the parking pawl can handle it. You should be able to skid the tires and the parking pawl not release. I’d probably not use and impact driver though if you can help it.

[jfandl]

I have the parking brake applied but I believe because the way the driveshaft and transmission interact, all the torque will be on the parking pawl.

I'm going to insert a large screwdriver in the driveshaft as BMW ISTA recommends and shows in a picture. I am not sure if my helper will be able to hold this while I loosen the 50mm nut but I sure hope so.

[E90convert]

Originally Posted by jfandl

I have the parking brake applied but I believe because the way the driveshaft and transmission interact, all the torque will be on the parking pawl.

I'm going to insert a large screwdriver in the driveshaft as BMW ISTA recommends and shows in a picture. I am not sure if my helper will be able to hold this while I loosen the 50mm nut but I sure hope so.

Put a breaker bar in the drive shaft and try to rotate it. Where do you hear the backlash? In the transmission or parking pawl or the rear gear? There may be more torsional wind up through the drive, shaft, rear gear set, and CVJ shafts. This would put more load on the parking pawl. I really don’t think it’s going to be a problem though. If it gives you any confidence in the advice, I was heavily involved the last five years in designing and testing a parking mechanism at work (among other powertrain activities). A vehicle should be able to get rear ended or pushed and the parking mechanism not break free or sustain any significant damage.

[crystalworks]

^What he said.

I know this is very anecdotal, but I have never worried about breaking anything loose with the trans in park. I have yet to see a parking pawl fail in my lifetime. Including working at an independent shop.

[jfandl]

Thanks E90convert & crystalworks You guys were spot on.

I put the car in park, then jacked it up to put on ramps (Couldn't drive it on). I bought the 250# torque wrench and the 50mm crowfoot wrench. I hit the nut twice with PB Blaster but not sure if it was able to soak into the locktite.
I got under the car with the wrench, removed any slack in the nut and gave it a few gentle tugs from near the end of the wrench. I felt it break loose with the tiniest of movement but movement none the less. I moved the wrench more and got move movement. I saw very little impact to driveline so I kept slow and steady pressure on each pull and the nut slowly came off.

Tips I learned. If you have a helper to keep the crowfoot on the nut while the other person turns the wrench, you can get about 4 clicks and then have your helper readjust the wrench. If you have a smaller wrench and the crowfoot, it's really really hard to move with a 15" handle.
Putting the new nut on tightens nice and easy, no issues and very easy to install in the 5 minute locktite window.
The hardest part of the install was getting the black rubber gasket under the lip of the pinion nut.

In case you're wondering why I had to replace the driveshaft, I had a vibration that was getting worse and then one day I took off from a stop light and felt something break loose. You can clearly see the bearing race is completely broken.