[Shrike360]

Thought I would get a better response from this subforum.

Have a bit of noise from the rear end. When above about 40, get a kind of "wuh-wuh-wuh" that increases in frequency with speed. At certain speeds, it gets a special pitch that makes things a bit louder (i.e. from ~56-58, 71-73). I realize there's a bit of brake noise in the second vid, but fairly sure that isn't what is causing it. I topped up the diff fluid last weekend (it ended taking about 400ml), and it seemed to help.

Any idea what the issue is?

[Gohan335i7]

[Shrike360]

Not sure if the noise is normal or not. My dad's 335xi is much quieter on the road (he is on 17s, basically the only difference). Could potentially go to a different fluid, but I feel like that may be just trying to cover up a problem.

[Shrike360]

Took some videos from the interior today. I'm still of the belief that it is the differential making the noise.

[avocet]

your diff is definitely ill!!!

I am not sure how hard it is to source an xi diff, but i got my diff(for a regear) off ebay for my 328i for under $300 shipped, and was in excellent shape with smooth bearing and no funk in the fluid.

that resonating noise seems like a classic diff symptom to me.

[Shrike360]

Rear end is the same as any other manual 335i, so not awful to find. May either see if it could be rebuilt, or source one through ebay.

[Stream]

I have similar sound in my 325i.
Hope it's wheel bearing, not differential =\

[avocet]

Originally Posted by Shrike360

Rear end is the same as any other manual 335i, so not awful to find. May either see if it could be rebuilt, or source one through ebay.

Thought gearing was different. I may be wrong tho...

[Volasko]

This should help you figure out the different gear ratios of all E9x's:

http://www.bokchoys.com/differential/GearRatios.htm

[Shrike360]

Originally Posted by Stream

I have similar sound in my 325i.
Hope it's wheel bearing, not differential =\

I'm having the dealer listen to it on Friday, before I order another differential. I'll update on what they say.

[Stream]

Originally Posted by Shrike360

I'm having the dealer listen to it on Friday, before I order another differential. I'll update on what they say.

Any news?

[Shrike360]

Dealer says it's my rear left wheel bearing that was the cause, diff was apparently quiet. Trying to get an independent to do the job, because I think $950 out the door was a bit much. Already got a quote for $550 OTD, so will probably go with him.

[Shrike360]

Tag you here to so you get a notification.

Originally Posted by Stream

Any news?

As a side note, didn't know that when an xi is in the air, you can make sure that all four wheels spin by turning off DTC.

[avocet]

Originally Posted by Shrike360

Dealer says it's my rear left wheel bearing that was the cause, diff was apparently quiet. Trying to get an independent to do the job, because I think $950 out the door was a bit much. Already got a quote for $550 OTD, so will probably go with him.

Ah lol! I assumed you had isolated the noise to the diff when you had it on jacks!

[Shrike360]

Originally Posted by avocet

Ah lol! I assumed you had isolated the noise to the diff when you had it on jacks!

Thought so too, dealer wasn't even sure what it was when they first took it.

As an update, got the wheel bearing replaced. Nice and quiet in the car, now.

[Meeni]

Usually a woo woo noise that follows speed is a wheel bearing, not the diff. Good luck.

[ramp]

Interesting thread. A couple of months had all fluids changed in my e91, manual 6 speed. Mechanic said the rear differential makes noise at 40 mph. At the shop they said we see this all the time. Do not rebuild, just replace with a good used one. I'll check into this after winter.