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

[bimmerboi318]

not a fun saturday night....

i noticed tonight a faint clunking from the rear of my ti tonight on decceleration. i didnt think much of it until it became louder. whenever i let off the gas, it sounds like someone is knocking on the underside of my car several times per second. i think its going the same speed as the driveshaft...but i could be wrong and it could match with the wheel speed. i've been told it could be a worn cv shaft, but im worried it might be a differential issue. i thought it might be a universal in my driveshaft, but it only does it under decel and there doesnt seem to be any driveability problems. no noticable vibrations, doesnt pull, etc...

if anyone has ANY info, please help me out here. im putting the car up on the lift tomorrow, but im a tad nervous about it. this is the first, not-so-good, noise i've heard from my car EVER.

thanks.

[motorsport]

If it is only on the deccel I highly doubt it is CV shaft, I think your right it might be torn up gears in your rear end, for that i would suggest a junk yard swap. If you have a couple buddies help and have access to a lift it isnt too bad.

[bimmerboi318]

well, i put the car on the lift yesterday and put it in 3rd and ran it while i inspected under it. the clunking was very noticable doing this and seemed to be coming from the front of the diff (UGHHH). upon further inspection (with the car NOT running) i found some play in the rear universal joint on the driveshaft. enough to make some noise. well i thought "phew, what a relief" until i remembered reading that the universals are not servicable...i need a new driveshaft. i felt around and didnt notice any play on the pinion shaft on the diff, although i cant be 100% sure there's no problem in it. i noticed some scraping noise from the sides of the diff, where the carrier bearings are, using a stethescope...but who knows how long its been doing that or if its normal.

so...my planned actions

1. replace driveshaft and hope it fixes noise

2. if it doesnt, replace diff...with a 3.90:1 lsd :)

[motorsport]

that is a good plan, and if it is the diff..you get an upgrade

[J!m]

Guibo is OK??

[bimmerboi318]

yes the guibo is fine to my surprise. i always joked about the germans using a rubber disc instead of a universal in the front of the driveshaft...but it lasted longer than the u-joint! i will replace that with the shaft. i located a shaft from a ti with 23000 miles from a junkyard in north carolina for only 100 bucks. so that should be fine from the sounds of it. we'll see what happens.

[mrnine]

Had some strange noises on my way home tonight after several hours of driving. Sound started after a couple hours of 75mph driving on the WV turnpike.

First noise sounded like a clunk from right rear (or maybe center) as if I had hit something in the road, though I didn't feel anything. Over the next 10 minutes several more random clunk/bangs like this. Looked underneath; everything looks perfect. CV boots intact, etc.

Limp toward home slowing my average to 55mph with several stops to confirm that things still look intact. Seems OK. Then the sound becomes more rhythmic clicking, much more consistent with a cv joint. The thing is, it's completely random and comes and goes. I drove for maybe 15 miles with no sound, then clicking came on immediately and loud. Then soft clicking for the next 15 miles 'til I got home.

It doesn't seem to me to vary in any way with acceleration or deceleration. I'm about to go out for a spin right now to try to get a better feel for it.

I'm starting to think diff. :( First major mechanical sounds from this car ever. Mileage is at just short of 130k. I changed diff fluid at around 100k so admittedly I was due if not overdue. Is next best step to drain the fluid and look for metal or does anyone have any other ideas?

[mrnine]

What was the outcome with this? Did it fix your problem? I've got some similar clunking/clicking I'm trying to diagnose.

Any help would be appreciated.

[mrnine]

Just to provide a bit more info...it seems to me that turning and braking have no effect on this sound. It's doing it fairly consistently now. The click is significant enough that I can feel it's pulse very slightly in my palm through the stick shift. I can't seem to get it to do it under heavy acceleration but that could just be that I can't hear it over the engine. It seems slightly more inclined to do it under deceleration and coasting. I put my windows down on my street and went 5-10mph and it seems that it would be loud enough that you would hear it outside of the vehicle fairly easily.

I have a busy day tomorrow but maybe I'll have time to run it to my friend's shop and get him to put it on the lift and see what we see/hear. Otherwise maybe I'll jack stand it tomorrow night and give it a listen.

Anyone who has any insight, I'd apprecaiate it.

[1996 328ti]

shock mounts
drive shaft center load bearing
guibo

[mrnine]

I'm not sure about shock mounts simply because the sound is currently so consistent with something that is making revolutions. Center load bearing or guibo would be more likely, but why should I be more inclined to expect that than say a cv joint? I don't even really know anything about these guibos. There had been a link to Pelican with replacement instructions but it seems to be an expired link. How can I check it? Would it be at all obvious in terms of visible wear if it was going bad?

The sound is such that the first time I heard it and it was acting more consistent, I was looking to see if something had dropped onto an axle and was rubbing somewhere.

Thx!

[mrnine]

I found the proper DIY link to Pelican for the guibo swap. The pics showed me what to look for to identify a failing guibo. I'll look at that and see what I see.

I still have fears though that it's a differential. Certainly someone on here has had a similar failure and can provide some insight. To reiterate from page 1:

- Started as a clunk
- Became more like a rhythmic clicking like a cv joint
- Seems slightly less inclined to do it on hard accel; turns make no difference, braking makes no difference
- Although it is rhythmic, it is inconsistent; sometimes louder than others
- Car has 126k and has been otherwise well maintained

[1996 328ti]

When I had a bad center load bearing I heard a noise only in reverse.

[weezer]

Definitely, absolutely....110% CV joint.
I have had many experiences with these when worn. Sometimes the clicking sound only happens when left/right turn, depending on which side, or deccel or accel......but when it clicks........always CVs.
When replacing them.......it is way cheaper on the labor to get a full halfshaft assembly and replace both ends of the CVs. Yep....two CVs for each halfshaft: on at the wheel and the other at the diff. So, when replacing the full halfshaft, you're replacing both.....who knows the other might be worn also. The labor cost to disassemble the halfshaft and only replace on CV is the same. If you buy a remanufactured halfshaft (1/2 of OEM price or less). If guibo or other center shaft issues, vibrations will be more prevalent.
Good Luck!

[mrnine]

Oh weezer, how I wish you were 110% definitely, absolutely right.

BUT...unfortunately, I decided to drain the diff and found a good bit of metal gear filings in there. Bad news...I'm bummed.

I know, I know...opportunity for an upgrade! But it sure don't fit my budget very well right now. I had always thought I'd look into an E30 LSD; I'm super busy though. Is it really that much more work to replace the half shafts on the swap? It seems putting in an E36 LSD would be less work.

But I guess the trick would be actually finding one. I'm feeling like this is going to put my ti out of commission for awhile 'til i sort all this out.

[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]

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