Diff Question, please help.

[socal318ti]

Hey everyone. Just recently purchased a 97' 318ti. I've had the car for about a month about put about 2000 miles on it. Its mostly free way driving, not a lot of stop and go traffic. Up until a few days ago everything was going smoothly until I started to get this loud howl from what im suspecting is the differential. It only starts to get noticable when I go above 40mph but gets really loud when I get up to about 80mph. Any advice would be great. Thanks so much.

[1996 328ti]

Is it a limited slip?
First cheap thing I would do is replace the diff fluid with Red Line.

[socal318ti]

Its not a LSD, unless the 97's came w/ them and I didn just have the diff fluid changed. It was a few days before the noise started happening.

[Jeff Spooner]

it may be your wheel bearing on one side. have a shop w/ a "Chassie Ear" check to make sure exactly where it is coming from.

[socal318ti]

Thats something my father suggested it after driving it. Im going to take it in tomorrow to find out whats really up. Hopefully not the diff.

[Jeff Spooner]

the wheel bearings are a more common problem. Most of the time it will be louder when you turn one way and quieter the other way due to load. If the noise does not change it will be the diff. I have a open diff from my 95 ti W/ 105,000 on it 3.45 ratio from a 5sp car.

[socal318ti]

The noise doesn't change when turning one way or the other but it does go away when I take my foot off the accelerator. The car has less than 90K miles on it.

[Jeff Spooner]

sounds like the diff. sorry dude. since you just had a diffy service done. check to see if there is fluid in it. if a shop did the work make sure you are there watching when they check it or take some where else to document if the fluid was low or not there at all. WE mechanics due make mistakes, not very often though.

[socal318ti]

Well ouch. Its going to shop tomorrow to find out for sure. Thanks.

PS. Anyone know any places in Socal to look for replacement diff?

[1996 328ti]

I think a wheel bearing would be a high pitched sound.
When my diff was going it was a groaring or howling sound.

[J!m]

I have stock (open) diff available for 5-speed ti's.

[socal318ti]

Hey J!m. It looks like it is the diff. How much for one and how much to ship to socal? Thanks everyone for the advice.

[2002tii]

If it is your diff I've heard that late 80's diff's off 528's and 325's bolt right on. These diffs are a dime a dozen here in LA at junk yards. Just one way to keep the cost down.

[socal318ti]

Can anyone assure me of that? I Don't want to go buy one and then be out of luck. But thanks for the heads up. I'm sure I can find one here in San Diego.

[1rstbmw!]

I had the same problem when I took my foot off the gas It had a loud high pitched squeak I got it fixed just about for free and havnt had any problems since.

[socal318ti]

Was the sound appearing when you took your foot off the gas or when you had the pedal depressed. Mine is is when the pedal is depressed and im accelerating, keeping a constant speed. If this is how yours was, what did you do to get it fixed for almost free?

Also I went back in and got the service records from the guy that I bought the car from. He had the oil changed, diff and transmission serviced only about a week before I bought the car. Looking on the invoice it says they put in Mobil 1 75/90 gear oil. Now im new to BMW's so any advice if this was the wrong kind of diff oil or something else that might have gotten messed up. Thanks.

[1996 328ti]

Can anyone assure me of that? I Don't want to go buy one and then be out of luck. But thanks for the heads up. I'm sure I can find one here in San Diego. They bolt up but you need different half shafts and make some other mods.
http://www.318ti.org/notebook/diff_conversion/index.html

That fluid they used sounds right.

[socal318ti]

Yah, thats what I thought also on the fluid. It just seems odd that I wasn't hearing any noise and then just a while after buying it it started.