Clicking noise in rear end...cv joint? diff? wheel bearing?

[weezer]

As far as I know.....depending on the size of the filings.......that is normal, to a certain degree.
That is why it is recommended to replace/flush/drain BMW differentials every year or 10k miles.
With the ticking, definitely the bearing in one of the CVs. And yes it is cheaper...labor-wise to replace the whole halfshaft with 2 new Joints. Think about it.....in order to replace one of the CVs, you still have to remove the whole halfshaft to disassemble one or both of the CVs. If you have a new halfshaft with 2 new/remanufactured CVs.....it will be removing and replacing. Besides, each CV has about 6-8 kex/allen bolts, that might be seized, to take off before you can replace the CV.
Good luck!!

[mrnine]

Hmm...well, I'm behind on changing the fluid in my rear as it is. So perhaps the gear filings are normal?

I'll take what filings I have and shoot a picture. Maybe I can get a decent closeup and include a penny or something for context.

I know that a "clicking" in many cases does indicate a cv joint. The things that made me suspect (beyond the filings) that it was something else is: Sound didn't start as a click, but a clunk and a bang. Then many miles of no sound before the sound became consistent. And even now it's not totally consistent; will occasionally go for a mile with no noise. CV joint failures in other vehicles have always been fairly consistent.

One other clue: I've found that if I run the car and coast, if I give it quick bursts of acceleration, I get the clunk at the moment the torque is engaged and then again when it's disengaged if that makes sense.

I'm still just not sure what to suspect. I guess I could always fill it back up with fresh fluid and get it on a lift and try to figure out where the sound is coming from. As it is, I had sort of given up hope.

Thanks...I'll try to get a pic of gear filings up here soon.

[mrnine]

Well, I looked through my gear filings and most were just itty bitty specs. I guess when I opened up the diff, I thought any filings were a telltale sign.

Below are links to pics of my largest fragment. This thing almost looks big here but the dime puts it in context. Think this is within reason to find this much scrap in my diff? Fluid was pretty dirty.

Consequently, this thing is barely thicker than the dime. I would estimate that the next largest piece that I found was 1/5 this size.

http://rich.mediabrite.com/318ti/gears/1.jpg
http://rich.mediabrite.com/318ti/gears/2.jpg
http://rich.mediabrite.com/318ti/gears/3.jpg
http://rich.mediabrite.com/318ti/gears/4.jpg

[1996 328ti]

Originally Posted by weezer

As far as I know.....depending on the size of the filings.......that is normal, to a certain degree.

My LSD was making a whirring sound for some time. I replace the fluid every spring before driving school season. A couple years ago the fluid was gray and gritty from the last time I had clean fluid. It disintergrated in a year. I ended up putting in the larger Quaife.

Those chunks are not normal.

[mrnine]

Hmm...so the question is: do I have both a failing differential AND a cv joint going bad? I just picked up some drive axles with cv joints used on eBay for $90 just in case. Either way, I figure at that price they might not be bad parts to have on hand.

Do you think the clicking and clunk that I've heard had anything to do with the differential?

[1996 328ti]

Clunks can be rear shock mounts too.
Pretty hard to diagnose problems over the internet.

[pdxmotorhead]

Diagnosing the rear end,

1. No play in any parts other than a small amount of wind up in the
rear end. Should be small, IE you can trotate the drive line a wee bit
with the wheels locked.

2. Yes if you can get a reman CV axle assembly its better because it saves the
disambly and rebuilt cost UNLESS you do it yourself. Its not THAT
hard. If you can get it out you can likely rebuild it. But last time I
price shoped this operation it was even cheaper than just the parts.

3. Its normal for small glitter sized metal to show up in the diff fluid,
NO shards of metal. I pull the rear diff cover annually to service
and inspect the internals. ALL my gearboxes get anual fresh Redline.

4. Rear ends are rebuildable. Any good mechanic should be able to do it,
tip: 4x4 shops do gear setup ALL the time. They may be a good option.
All it is is 3 or 4 bearings and some gaskets and shims(Usually you
re-use the same shim set and check the gear setup. 9 out of 10 times its
perfect. not rocket science. Its only scary the first time.... Its usually
economical becasue you can remove the diff an take it in for a
benchtop rebuild. Typical setup for a gear set is $150 (Usually
including shims if needed.)

5. Non serviceable u-joints Are usually serviceable. Find a GOOD
drive line shop. IF they cant service them it would be very un-usual.
My local shop charges about $35 to do the swap plus the parts.

Good Luck
Dave

[budget76]

Responding so I can find it again, sounds similar to my current problem