Can I come crawling back to this board for some real expertise? Tough vibration!

[Tiger]

Not only that... his car is a 2001 too... Costco wheel balancer are rarely ever calibrated. I still think it is wheel balance issue. You don't need roadforce balancer... but a good balancer.

My uncle got a new machine and everytime I go there, I manually calibrate his machine before I do any balancing. He and his crew never calibrate the machine. Before this machine he had a good Coat wheel balancer but something was seriously wrong with it. We could never calibrate the machine... I would run like 5 or 6 calibration and the result are horrible. The machine would read zero but if I keep spinning it to check it, it would throw new weight readings... never ending.

[DanDombrowski]

Hey all, its been awhile since I've sold my E34 and posted here. Since I've been very much lacking stimulating automotive conversation beyond clear corners, wheels, and oil type discussions on the other board, and because I have an extremely confusing vibration problem, I've come here to throw myself at your guys feet for help. Since you all actually work on some of your cars, I was hoping someone could shed some light on this. This is for my E46 (which has a driveline very similar to the small 6 E34 525i, actually). The E46 is a 2001 330Ci with a 5spd manual.

Okay, holy crap, I am completely, thoroughly, and utterly confused. I've been having a rear end vibration for some time that I asked about here (http://forum.e46fanatics.com/showthread.php?t=563764) but didn't get any responses. I did my test of lifting the car and running the engine tonight, and I got very strange results.

With the wheels on - MEGA vibration, way worse than driving the car. Nothing until about 40, then a pretty big peak (probably the biggest) at 45, then a little less at 50, then another peak at 70, slows down a bit at 80, and then gets progressively worse from 90mph +. Heres an odd thing - when driving the car, the worst vibration is at 82mph, where there is the least with the wheels off. When driving, there is very little vibration at 45mph.

With the wheels off - very, very, very little vibration, but I can still feel something slightly. I can also notice what I THINK is a slight bit of runout on the rotors radially, then seem to be not rotating perfectly round, but its not completely obvious. Could be an optical illusion.

Now, here's the crazy part. I put the car in 5th, let off the clutch, and let it idle at 20mph. With the wheels off, there is a noise like what you would think the inside of a windmill sounds like. Its a clinking, clunking, metal gear noise thats rythmic, but random, if that makes any sense. I had my GF rev the car up to 40-50, and it does SEEM to get a little worse, but its very hard to tell. If you put your ear directly next to either wheel hub, it seems to come from the hub. If you stand behind the car, it seems to come from the differential.

As crappy as a busted differential sounds, I'd rather pay $200 for a used diff than $400 for a rebuilt driveshaft. I am just at a complete loss, I'm very confused by these symptoms.

A little more information about the tires. I got a flat a little while ago, Costco finally got my new tire in. The flat was on the LR. I had them put the tire that was on the RR on the LR, and the new tire went on the RR (to balance out the camber wear and because the RR wears the fastest). Both wheels balanced to 0.00 on their 2 position machine, but it wasn't a roadforce machine. Also, the vibration in the car didn't seem to be affected by this tire change at all.

Any ideas? I'm thinking either the differential is all sorts of broken, the wheel bearings are shot (although there is no play in the wheels that I can tell), or the CV axles are messed up somehow. I want to throw tools at the wall at this point. Thanks for all the help.

[Blitzkrieg Bob]

How's the subframe?

Did you check to see if it has torn out on the body? (common problem for some e46s).

Bad rear end makes more noise then vibration, so I'd go for the wheel bearings

[DanDombrowski]

Yeah, I know about the subframe problems. Theyre not typically known to cause vibrations, and I've inspected for tears several times. There are no tears in the subframe that I see. Thanks for the response. I'm thinking it has to be either wheel bearings or a bad diff.

[Blitzkrieg Bob]

Yeah, I know about the subframe problems. Theyre not typically known to cause vibrations, and I've inspected for tears several times. There are no tears in the subframe that I see. Thanks for the response. I'm thinking it has to be either wheel bearings or a bad diff.


Change the fluid in the diff and look for metal flakes

[winfred]

i can't think of anything that i've seen on a e36/46 that would vibrate in the assend, the axles can get a little clunky when running on stands as they are at a bit of a odd angle so don't let that fool you, the wheel bearings suck in e36/46s but generally make no more then noise or a buzz, e46 diff mounts seem to suck but so far i've not seen more then a nasty clunk when going from forward to reverse or on/off the power, brakes are not really going to effect anything unless you are using them, have you tried rotating the tires from front to rear? that if it is a issue will change the problem

[DanDombrowski]

Bob,

Yes, I was thinking this as well. Didn't have time to get to it today, but this is next on my list. If the differential is the one making the noises I'm hearing, then there would be LOTS of metal. I wish I could have taken an audio clip or something. I think this test will tell me a lot.

Thanks.

[DanDombrowski]

Wow, thank you so much. This is solid information. So when the rear wheels sag, this throws the CVs at an odd angle and they vibrate more? I never thought of that. Is this a consistent thing, or "some do, some dont" ?

I suppose to check this I could jack up the rear trailing arm and put another jack stand underneath it. This is very meaningful, although I would still be confused as to what is causing my vibration.

I've posted a lot of information in other threads on the other boards about work I've done/need to do that I didn't include here. My rear diff bushing is indeed cracked, and I do need to get that fixed, as I am getting a clunk, but youre right, I wouldnt expect that to cause any vibration.

As for the wheel bearings, I have another symptom. Between 20 and 40 mph, I get a woomp-woomp-woomp noise from the rear. It doesnt vibrate, but it makes the noise. I've tried leaning the car left and right, but haven't noticed any difference in the noise depending on which direction I'm turning, so I had a tough time thinking it was the wheel bearings. The grinding noise in the rear though might also be a part of it.

I can't rotate the tires, because the rears are wider than the fronts. Best I could do is mount the fronts on the rears when spinning the car stationary on a lift.

I have tried fitting the spare (not voluntary, had a flat) and that didn't change the vibration much at all.

So you think the fact that I was getting a big vibration with the rear end lifted is false because of the axle hang?

[DanDombrowski]

This is interesting. I have 2 costco locations close to me. One is on the way to work, one is close to home. The one that is close to home has 2 Coats machines, one the "2 position" one, and one older style you see in most shops that has the older display (not sure if thats a good description or not).

The costco by work is brand new (less than 3 months old) and has all new machines. I would THINK that they've been calibrated not too long ago, but they may very well be off. The Coats machines with the 2 postion balancers are the XBR1800 IIRC.

The reason I never thought it was a wheel balance issue is 1- I get the woomp woomp noise at 20-40, and 2- I swapped around tires all over the place and the vibration didnt change much if at all. Also, I had a bit of vibration before I even got these tires, which I bought because I found the old ones were cupped, which I attributed the vibration to, but was wrong.

I will take it by the costco next to me and have them give it another try. Thanks tiger!

[Sixdown]

From my experiences, the woomp woomp noise came from the tires. It may be the new one you had put on the rear. In my cases it has been faulty tread or uneven wear on the front or rear tires. It can be wheel bearings too. Anything uneven can cause the noise.

[DanDombrowski]

Well I had the woomp woomp noise with my old tires, the eagle F1 GSD3s, which had cupped, all 4 of them. I got 4 brand new BFGoodrich Gforcesports, and the noise hasnt changed. Put about 4000 miles on them, got a flat, put the spare on, noise didnt change. Finally got the new tire on, noise still hasnt changed. On top of that, I rotated the rears, so anything that would have worn on the inside edge with the high -camber the E46 runs would have been on the outside now anyway, so it would be like 2 new tires. Even still, no change.

Its very odd, the woomping noise does seem like it would be tires, I just cant affect it at all it seems.

[winfred]

probably a wheel bearing on the way out, the rear's don't usually change pitch with turns like the fronts do, more then likely the right side from my experience, you can hear them usually with a mechanics stethoscope by listening to the brake splash shield with the wheels turning, the shield acts like a speaker and you can listen to one side and then the other and compare


Well I had the woomp woomp noise with my old tires,

[Tiger]

The tire cupping really bothers me... tire cupping is usually because of bad shock... being a 01 makes it seems impossible to happen but if I recall correctly, you work in NYC so there is alot of potholes and road issues you are dealing with. The whoompa whoompa may be the sound of the struts is making of compression and expansion.

Are you positive it is all 4 wheels cupping? Not just two on one side of the car? If they used front-back tire rotation, then it should have been one side only... Check your new tires... see which tires are cupping.

[DanDombrowski]

Wow winfred, I'm truly impressed, and very thankful for these suggestions. I never would have thought of that. I always suspected a bearing for the woomping noise, but never decided that was it because it never changed when I leaned the car to the side. If they don't change pitch like the fronts do, that would definitely explain it.

Now, are you thinking that the wheel bearing going out is also what is causing my vibration? Or just a coincidence and you're answering the question about the woomping noise? Theres no play in the bearing when I yank on the wheel, either of them. Is this something you normally see (a bearing making noise, going out, causing vibration, but with no play in it that can be felt by hand) ?

Thank you very much for the help. The responses on this board have been 10X better than anywhere else.

[Ross]

My experience is a bearing will make lots of noise before any noticeable vibration. Since moving tires around doesn't make a difference I'm inclined to rule that out also.
Get you trailing arms in a more normal position, not hanging at full suspension travel, then turn the wheels by hand to feel for any "catch" during rotation. My guess is a CV joint.

[winfred]

in maybe 90% of the bearings i do (and i do a ton) on the back of e30/36/46 they have no movement and sometimes don't really make noticable noise till you get down to the bare hub with the axle pulled then you give it a spin and it sounds like ****, these bearings when bad just don't sound off very much when unloaded, it's generally a nasty spot in the race that looks like electrolisys has pitted it and when not loaded with the weight of the car it just skips over the bad spot, when ignored long enough it will indeed develop play, i have had a few come in that the wheel looked like it was about to come off and the brake was pretty much holding things together

[anonymous1]

Hi,

Sorry to bustle in on your initial query, just noticed Winfred's comment about the diff mounts and I'm wondering if I could have this issue.

I seem to get a clunk coming from the rear centre when pulling off and then if I reverse. Also occasionally when I switch gear. I've looked with it up on ramps, while e34.sport got some air speed up and cannot see/feel anything wrong with the driveshaft where it meets. (although I could be missing something) Also had a garage look and they could not see anything wrong, so have said to go back if gets worse.

Anyway, just wondering if there's a way I can check the mounts and if it's something I need to worry about immediately? How easy would it be to change the mounts?

Thanks in advance and again apologies for jumping on the thread. (I'll start another thread if needed)

[DanDombrowski]

Tiger,

No, I don't work in NYC. I live in South Florida, where I have to admit the roads are pretty smooth. Also, when I found the first set of tires were cupped, I replaced all 4 shocks, the shock mounts, and the RTABs.

After I replaced the shocks and the RTABs, I got new tires in the rear and an alignment. Still had the woomp woomp noise. So, I pulled the front tires off and those were cupped as well, so yes, all 4 tires cupped. They were relatively worn (less than 20% left on fronts, less than 5% left on rears) Goodyear Eagle F1 GSD3s. Replaced the front tires as well (so had 4 new tires). STILL had the woomp woomp noise.

The new tires do not appear to be cupping, but its hard to tell.

[DanDombrowski]

Winfred,

The woomping noise has been going on for some time, but I still havent noticed any play in the bearings. I dont mind replacing the bearings (as they'll probably have to be done eventually) if you think thats what may be causing the vibration.

Unfortunately, after lifting the car and spinning it, it seems my vibration has become a lot worse. It never used to vibrate at 45mph or below, and now it definitely does. I'm guessing that I may have damaged the CV axles by spinning the tires with the rear in the air? I've done this before on the 525i and the suspension wasn't nearly as extended, so I didn't really think about it.

I wonder if that means that the vibration was originally caused by bad CV axles and this has made it worse, or if I've just added to the loose parts in the rear end and I have to replace the CV axles as well now. Well, that was a dumb move on my part. Do you think spinning the axles suspended would damage them, or just cause them to move more when unloaded and they'd be fine when I lowered the car again?

Thanks for all the help on this.

[Tiger]

So you bought the car used... and has that noise ever since you bought it... big mystery.... Did you ever let a body shop take a look at your car? Check for trueness, possible body repairs, etc?

How about alignment shop? Did they notice anything out of spec?

[DanDombrowski]

I just changed the diff fluid today. No metal flakes, fluid looked totally fine. Definitely not the differential.

[winfred]

i doubt you hurt the axles running it up in the air, the bearings shouldn't really cause more then a barely noticeable buzz


cap't slow, pry around on the diff and subframe and see what moves, if it makes noise something is moving

[Tiger]

I think you are on the right track to fix this after al these information you provided.

[DanDombrowski]

I bought the car used in June of 2006, and when I picked it up, it was the smoothest car I've ever driven. The vibration slowly came about middle of last year.

[DanDombrowski]

So if I didn't hurt the axles and the diff is fine, were back to my original suspicions - flex disc, CSB, and rear diff mount.

I plan on having all 3 of these things done anyway, so hopefully it will either clear this up or at least shed some light on what is going on. Thanks Winfred!

[DanDombrowski]

Quick update - jiggling/noise in the rear got worse and took it in again. This time, detected a tiny amount of play in one of the bearings. Replaced both. Car feels much more stable in the rear, but still have high speed vibration. With the jiggle gone, I can tell that the vibration is a out of round/out of balance issue. So, gotta track that one down....

Thanks for the help everyone!