Noisy diff maybe not sure

[hisbikes]

I recently got my wife a 95 318Ti auto. There is a high pitched sound coming from the rear. Becomes noticable from about 50kph onwards but does'nt seem to get louder with speed increase or going round corners. The sound is remenecent to a Cicada (an insect here in New zealand that makes a high pitched noise on hot summer days). It's not overbearing but noticeable. (Can be clearly heard with the window open and passing other cars or when driving close to sidewalks. Has anybody experienced this?

[1996 328ti]

Is this an open diff?
I kinda doubt that the diff is going.
You can always drain the fluid and feel for metal fillings.
My money is on wheel bearings.
Wheel bearings are generally high pitch.
When my diff went is was more of a low moaning sound.

[hisbikes]

maybe but these don't get louder as you change direction or put load on them and also don't seem to change much as the speed increases

[1996 328ti]

OK. Make sure you have all your lifting pads in place.
Know you, those hockey puck looking things.

[hisbikes]

only had the car for 2 weeks, so i don't know them at all

[hisbikes]

where are they situated?

[1996 328ti]

where are they situated?
Look at
http://www.pelicanparts.com/BMW/techarticles/E36-Jacking_Up/E36-Jacking_Up.htm
The pad is fig 4. You should have 4 of them.

[rennerb]

95 318ti with auto tranny

I will be interested to hear what you come up with. Same thing with my car, after about 20 mph I hear it constant sound no change with speed with the windows down, I checked my diff fluid and it was full and clean, serviced it and I thought it reduced the noise some but it could be one of those "car runs better when its clean" things.

I did find one of the disk guards, rear RH, was bent making light contact with the rotor and that quieted it down a bit but the sound is still there.

I sort of gave up on finding it figuring it might be my transmission, friction plates (automatic) since the previous owner never serviced it and when I did the fluid was very black, coupled with the fact that it slips a bit at certain times.

[hisbikes]

but now I'm really confused, forgive my ignorance but what do these little blocks for jacking the vehicle up have to do with the the high pitched whine coming from the rear?

[stormos]

jack it up to take a look ?

[hisbikes]

that he was talking about some type of block thats at the diff that may be missing or something like that.

[J!m]

If the puck is missing the air can 'whistle' across the open hole at certain speeds....:rolleyes:

[stormos]

pretty sure mine was not a hig high pitch sound when mine went.... but it was jsut a steady rumble i believe. i can't remember and it was only a month or 2 ago!

[cali-ti]

ring/pinion are more high-pitched, but it changes pitch with speed and load so it doesn't sound like what you have. maybe an air leak somewhere?

[stormos]

ah! remove the rear bench and drive with it out for a while. When my diff was shot i had the rear bench out for some other reason and it was rather loud i recall. either way it might help to isolate where the sound os coming from. get a mate to listen while u drive...

[Dusty]

I have a '96 ti with the same symtoms. A high pitch sound or whining coming from underneath. The sound does not change with speed. Some people think (LOL) its a turbo/supercharger kicking in. (I wish!) I was thinking of having my differential drained a flushed, if there is such a term, also the transmission, but would like to know what the problem is.

[BeardoMcWeirdo]

Just a heads up to everybody who has read this thread I've come to find out that this sound that everybody is talking about is probably related to the differential Output bearing... This part usually goes for around $50... Many people replace the entire diff which isn't the cause.. From what I've read some people have gone 50,000 or so miles on it with no problem.. Hope this helps...

[stormos]

i'll remember that when my new one goes again ;)

[bmwkru]

Just a heads up to everybody who has read this thread I've come to find out that this sound that everybody is talking about is probably related to the differential Output bearing... This part usually goes for around $50... Many people replace the entire diff which isn't the cause.. From what I've read some people have gone 50,000 or so miles on it with no problem.. Hope this helps...

Has anyone verified this? I recently bought a 96 tia and have the same problem. The odd thing is that it the noise decreases when you let off the accelerator (it does not decrease very often;) ).

I really want to get if fixed but their are not very many people in my area that work on BMW's so I need to tell them what to replace or look for.

[jkilla71]

I recently got my wife a 95 318Ti auto. There is a high pitched sound coming from the rear. Becomes noticable from about 50kph onwards but does'nt seem to get louder with speed increase or going round corners. The sound is remenecent to a Cicada (an insect here in New zealand that makes a high pitched noise on hot summer days). It's not overbearing but noticeable. (Can be clearly heard with the window open and passing other cars or when driving close to sidewalks. Has anybody experienced this?


I have a 95 Auto and it sat in the garage for a year or two without anyone driving it (For some reason I liked driving the A6 I had at the time). After coming to my senses I put it back on the road at 89K. The rear end under acceleration sounded like a jeep on the highway with big tires. I took the car to Jiffy lube and it still made the sound after that but the noise has gone away since I have been using the car everyday. I can't remember when, but I do live in south Florida now and the car doesn't see those cold PA mornings anymore so that could be a variable too. The car has 155k on it now and the noise has not come back.