[E36graduate]

Just an FYI.....I've been chasing down a humming noise from my front drivers side wheel area for about 10,000 miles (heard from the inside). The noise is getting worse and is driving me crazy.

Decided to get under the car and check out a few things. Noticed that the plastic and metal pan below the front differential was quite dirty/oily. Noticed some oil around the seals on the output seal on the front diff....not a good feeling.

Opened up the fill plug on the front diff...stuck my finger in there....nothing....not a good feeling.

Opened up the drain plug on the front diff......abot 1/4 quart came out....OMG. No metal came out....sigh.

Refilled with about a quart of 75/140...heavier oil.....put everything back together after cleaning the dirty areas. Took for a ride.....noise still there.

Thinking the front diff was toast....started shopping around....only 11 front diffs are available.....and they are in Germany. None in the states. $1600 + shipping.

Started looking at used....only 2 cars in the country are available, I am told. $1300 shipped. These were wrecked cars that were parting out.

Couple of local guys think they could rebuild the differential.....nothing in stone yet.

Bottom line.....stay on top of your fluid changes underneath!!

After putting my car on a lift yesterday and driving it in the air at about 2000 rpms in 4th gear...my mechanic with his stethescope pin pointed that my passenger side front wheel bearing was pretty bad. Just an FYI...my mechanic and I both thought it was the front drivers bearing.

I hope this is the problem seeing that the availability of front diffs are rare/expensive! We listend to the front differential and my mechanic said it sounded fine.

[orangedawg]

Front diff isn't too hard to change (if you need to eventually replace it), but does take some work. Lots of wrench turning, but if you are a decent backyard mechanic, you can do it. Weird thing on our cars is that the front axles go THROUGH the oil pan. Odd. Diff attaches to oil pan. You don't need to remove oil pan, though.

If you need a front diff, there is this car on ebay (listing is for transfer case, which is pretty cheap BTW) and he may have front diff. Just ask him. http://cgi.ebay.com/ebaymotors/ws/eB...K%3AMEWAX%3AIT The lsiting says it's for an 06 325, but the car is a 07 328xi with 33k miles (see VIN tag in listing pics).

[baron62]

Bearings don't seem to last as long as they used to on older cars.

[E36graduate]

Changed the passenger front bearing and car is quiet as a mouse now! Very odd that the humming noise sounded like it was coming from the drivers side......oh well, both front wheels have new bearings and my car is quiet again.

[jackw]

my outer shaft bearing on a 2009 328Xdrive is burned out. The car is out of warranty. Too bad, the dealer told me the bearing is not available as a single part and I have to buy a whole new diff ($2050). Can have a salvage differential from a junk yard for $700. Would prefer to get a sole bearing but I can't find it. Who's your mechanic and where may I find the specs of this outer shaft bearing?

Many thanks from Quebec

[Eracer76]

Originally Posted by E36graduate

Changed the passenger front bearing and car is quiet as a mouse now! Very odd that the humming noise sounded like it was coming from the drivers side......oh well, both front wheels have new bearings and my car is quiet again.

Where did you get the bearings and for how much, if you don't mind sharing?

I think my car is needing wheel bearings soon, because its not very quite anymore, its kinda sounds like noisy tires/road noise, but the noise didn't change at all when I put new tires on 6 months ago and Ive got 60k on the car now

[TeroRider]

Originally Posted by jackw

my outer shaft bearing on a 2009 328Xdrive is burned out. The car is out of warranty. Too bad, the dealer told me the bearing is not available as a single part and I have to buy a whole new diff ($2050). Can have a salvage differential from a junk yard for $700. Would prefer to get a sole bearing but I can't find it. Who's your mechanic and where may I find the specs of this outer shaft bearing?

Many thanks from Quebec

Darn, I tought dealers are rip-offs only in Bulgaria! xD Like OP said, you can change only the bearings. If your car is not under warranty just do it at a trusted local service. You will have absolutely no problem.

[E36graduate]

Sorry for not following up, been neglecting the 335xi qnd playing with dirt bikes for a year. Made about $3500in profit and going to dump some money into the bmw!

Not only were the wheel bearings bad, but q lot of noise was coming through the shot coil overs. New h+r springs and bilsteins made her smooth and quiet.

[MtBMW73]

Originally Posted by E36graduate

Opened up the fill plug on the front diff...stuck my finger in there....nothing....not a good feeling.

Opened up the drain plug on the front diff......abot 1/4 quart came out....OMG. No metal came out....sigh.

Refilled with about a quart of 75/140...heavier oil.....put everything back together after cleaning the dirty areas. Took for a ride.....noise still there.

Thinking the front diff was toast....started shopping around....only 11 front diffs are available.....and they are in Germany. None in the states. $1600 + shipping.

Started looking at used....only 2 cars in the country are available, I am told. $1300 shipped. These were wrecked cars that were parting out.

Couple of local guys think they could rebuild the differential.....nothing in stone yet.

Bottom line.....stay on top of your fluid changes underneath!!

I am resurrecting this old thread to provide additional encouragement to E9x xDrive owners to change your car's front differential fluid. Here's my story:

I have a 2013 E92 with a 6MT with about 83K miles on it. Last month it started developing a whine at low speeds, independent of engine speed. At first I thought it was a wheel bearing, but it was coming from the center of the car (rather than one side or the other) and did not change when weighting/unweighting either side. I took it to a local shop and they believed it to be coming from the transfer case, but not 100% certain. I changed the transfer case fluid and that had no impact.

So rather than blindly replacing the transfer case, this week I took it to a European specialty shop. They concluded the noise was not coming from the transfer case, but rather the front differential. They drained the fluid and noted only about 200 ml came out. Capacity is 600 ml. They refilled with the correct amount and that did not eliminate the noise, so the next step is replacement of the front diff.

The shop noted that there was no evidence of any leak, so where did the missing 400 ml go? I guess it just gets burned off...? BMW says this is a "lifetime" fluid and no change is necessary. The definition of "lifetime" is debatable, but one would expect it to be longer than 83K miles. The technician said the manufacturer of the differential (ZF) would disagree with the lifetime recommendation and suggested the fluid be changed at least every 40K miles.

So if you haven't changed yours and your car has more than 40K miles, consider it borrowed time and put it on your to-do list.

[alexl11]

I have a whine on my 09 328xi with 170k, I just dumped a bunch of money into it fixing oil leaks and now this. Did you end up getting the diff swapped, MtBMW73?

[MtBMW73]

Originally Posted by alexl11

I have a whine on my 09 328xi with 170k, I just dumped a bunch of money into it fixing oil leaks and now this. Did you end up getting the diff swapped, MtBMW73?

I've since sold this car, but the story of the noisy differential is a tragic one. The shop replaced the differential, which believe it or not, didn't fix the noise -- it was the transfer case. They totally (and embarrassingly) misdiagnosed the source of the noise. So they replaced the transfer case, and lo and behold, the noise was gone. So my car got both a new diff and a new transfer case. I sold it immediately after that.