2005 - Lateral Play in Front Drive Shaft - Transfer Case End

[SAR]

Did an oil change on my daughters 2005, which is here for an annual visit, today. She lives over 1000 km away, in an area where there are no BMW dealerships or shops with a lot of knowledge of the car, so I'm trying to get as much mtce work done as possible before the vehicle goes north again and have worked my way thorough most of the punch list. However, one thing has left me unsure if it is an issue or not.

As I was under the car, I checked the drive shafts and found that the front shaft U-Joint, at the transfer case, had lateral play (perhaps a total of 6mm / 1/4") in one direction only, but no rotational play. There was no lateral or rotational play on the U-Joint at the front end of the shaft.

I would normally think this points to a bad joint, but there are no drivability issues, which given the amount of play left, me wondering if this is normal and a design feature of the shaft (visually the joint looks OK).

Did a forum and google search and didn't see anything similar, except one post with the same question but no responses and another with the comment that a dealer said lateral play in one direction was normal (but that then went on to say the shaft was replaced, with no explanation leaving me uncertain why), so am hoping someone can enlighten me.

[E38flagship]

Your saying basically half of the U joint has play? I had the same problem I had very slight play in mine, it’s like it had “egged” out the cup where the needle bearings are. I got a new drive shaft from these guys I have over 50k on mine also has serviceable u joints

https://www.wholesaleimportparts.com...shaft_2005.php

[SAR]

Tx for the link

After making the post, I decided after looking again that the joint was going bad and ordered a shaft that should be here tomorrow / monday. I'm just on my way out to take the old one off, so the job is ready when the new shaft arrives.

The punch list on the car has grown over the last 10 days...... Before I found the drive shaft issue, I ordered a Foxwell NT 510 so I could look for an airbag code as the lamp is on. Very impressed by it so far - so much so I am going to order modules for my old (98) jag and 99 Suburban I use as a boat hauler. If they read as much as the unit does on the BMW, it is good value for the price.

Downside, is that the Foxwell also showed a few transfer case codes, so that expanded my work program so the job grew to include a change of transfer case fluid (at least). I doubt it has ever been done and I found a 54C6 code had been set which indicates a fluid change is required. After reading on the process, and other Xfer case issues, I also wonder about the state of the actuator gear and may just pull it and look at it while I'm at it as it seems like an easy job.

Good thing I haven't got much else to do with my spare time 😀

[SAR]

Update on my post.

As the attached picture shows, the joint was toast, Both bearings on the axis with play were history and the needle bearings long gone. The bearings on the other axis as well as the joint at the front of the shaft were OK. The amount of damage wasn't visible until the shaft was off the car.

Why this made no noise or didn't cause vibration is beyond me, but no doubt the shaft was a candidate for failure at some future point.

Removal was a piece of cake. 8 torx head bolts and 10 minutes to get it out. Installation should be as easy when the new shaft arrives. fingers crossed it is an exact match as clearances are tight.

The Foxwell NT510 showed that the transfer gear oil needed to be changed (code 54C6 was set), so I bought a litre of fluid and then decided that while I was at it, I would pull the actuator motor and check the actuator gear wheel on spec as the car is at 195,000 km and I expected it might need replacing. As the attached shows, it did - with tooth wear shown that matches what I saw on many posts. Given the amount of wear I found, I'm surprised there weren't more codes set. As it was the worm gear on the motor can only just have been making contact to rotate the gear. I expect it wouldn't have been long before the gear wheel failed and more codes were set& the car went into the default state.


Removal of the actuator *should* be simple, but I found that the bolt that passes thru the frame bushing of the transmission support was seized inside the bushing and took a lot of work to free (the transmission support needs to come off to give access to remove the actuator motor). That 30 minute job ended up taking 1.5 hours......

As many have reported, from the untouched grease on most of the gear it never rotates more than ~45˚, so I've reassembled after rotating the gear wheel 180˚. I expect this should be OK for the rest of the car's life .

Another finding was that the transfer case oil had been changed at some point in the past. As I know the car had been maintained from new by the dealer my daughter bought it from, I expect they did the change. What was sad was that I found the crush washers on the fill and drain plugs were missing - not a huge deal as the case sealed OK, but without the washers the bolts were very difficult to break loose. More worrying, and I suspect part of the reason the gear wheel had so much wear is that I got a full litre of oil from the case. The spec for the ATC 400 box is 0.8 litres when full and at ambient temp. It calls for a refill of 0.69 litre also at ambient, so I should not have got that much out. I think what happened is that the tech doing the change was working on a cold box and filled until fluid dripped from the fill plug orifice - but that is only the correct procedure if the box is at operating temperature, not when it it's cold.

I think by overfilling as they did there was likely a lot of pressure inside the case that could have impaired operation of the transfer clutches and contributed to resistance during the actuator operation and calibration sequence leading to the gear damage I found.