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Mike X
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Discussion Starter · #1 ·
Does anybody have experiences with a whining noise coming from the rear differential of a Z3? You only hear it with the top closed, around 50 mph, then it disappears completely at higher speeds and comes back around 75/80 mph. Mileage of the car is not even 30kmls. The whining noise was not always there. At some point in time it started and gradually increased. A BMW service Rep. claimed this is normal, can not be repaired and may happen again with a brandnew differential. Any thoughts or experiences? :dunno: THANKS!!!
 

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The diff in my '01 2.5i whines, too. It whines at the point where the car is not quite coasting and not quite accelerating. But I do not hear it when the drivetrain is under load.

I am going to try changing the diff oil to Red Line and see if that helps. My brother, who is a very experienced mechanic, told me not to expect that to fix it, though.

Mine now has 98,000 miles. It has whined ever since I got it at 75,000 miles. Mine hasn't failed yet, so I hope it is just an annoyance and not a potential breakdown coming.
 

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I changed the fluid on my 96 to Red Line, but it didn't help much. This winter I might change the wheel bearings, the right rear sound funny and has a little grease coming out (not sure if that is normal). After that :dunno:
 

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Differential Whine

I have the same condition @ 50mph, previous post pretty much laid this out as normal and not indicative of some pending catastrophic failure. Another point made in previous post pointed to the fact that we sit almost on top of the differential and the sound is magnified because of this.
 

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Mike X
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Discussion Starter · #5 ·
Thanks for the feedback. Hearing that Red Line did not help much helps me saving some money where it is not needed. Also good to hear that nobody with this whine has exprienced catastrophic failure (yet)... So I guess I have to live with that whining, but other than that the car is a lot of fun!
 

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Very common problem. Mine did/does it as you describe.

I originally replaced the diff fluid with Amsoil 75w140 and the noise was greatly subdued at some speeds, and eliminated at other speeds. Recently, the dealer had to replace the diff cover, which meant emptying and refilling of the diff with OEM fluid again.

And within 1000 miles, the whining returned. D'OH!

So when I get some time, I'll be refilling with Amsoil.

-Warr
 

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Learning to drive...
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Amsoil diff fluid (75w-90) works great indeed. Also try adding some limited slip additive in there. I use BG LSD with great success.

Florian
 

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Hey guys, i know this thread dates back to 2006, but i have the exact same problem.
gonna try changing the fluid next week. Hope it works.
 

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The Arkleyologist
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I've had two previous Z3s, one with 110k and another with 67K and neither one had an issue. I recently purchased a 2000 Z3 Coupe with 102K and it defintely has that exact whine as described in these posts. I will change to the Amsoil differential fluid. What is BG LSD?
 

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Mine is over 250.000Km. the sound came up around 180.000Km. BG LSD is a gear fluid additive:

BG LSII
Limited Slip Axle Additive Concentrate
BG LSII is designed to prevent chatter in plate and clutch type Limited Slip Differentials. BG LSII may be used with any GL-5 gear lubricant in limited slip applications. It is also excellent for eliminating chatter in full-time four wheel drive transfer cases. The ingredients in BG LSII smooth and quiet operation of gears in the differential and fortify the additives in the gear lubricant.

http://www.bgprod.com/products/driveline.html
 

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One last question if any1 can help,
What shall i use as fluid? the original BMW or Amsoil diff fluid (75w-90) or Swepco oil?

Thx
 

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Mine has done that ever since I bought it with 65K miles on it. It whines when not accelerating, just when coasting at speed. It's not gotten any worse. I had the fluid checked and it's in good shape and at the proper level.
 

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Me too since i got mine 3 years ago with 100k it whines when decelerating or accelerating at very low speeds. It***8217;s not gotten any worse since. I got used to it but every one who gets with me, directly asks "what is that noise?" it's like riding a Z3 with a jet engine! :p
So I***8217;ll try changing the oil since some ppl had posted that it helped or even eliminated that noise, no harm from trying, but still don't know what type is best. I think I***8217;ll go for Mobil 1 :s
 

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Mike X
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Discussion Starter · #15 ·
Me too since i got mine 3 years ago with 100k it whines when decelerating or accelerating at very low speeds. It's not gotten any worse since. I got used to it but every one who gets with me, directly asks "what is that noise?" it's like riding a Z3 with a jet engine! :p
So I'll try changing the oil since some ppl had posted that it helped or even eliminated that noise, no harm from trying, but still don't know what type is best. I think I'll go for Mobil 1 :s
Well, I am the one who started the thread back in 2006. I never ended up trying another differential fluid, since BMW decided to exchange the diff with a brand new one, during the last month of the 4-year-warranty. Worked for me. Still have the car, no whining anymore. :bow:
Hope the different fluid will work for you!!!
 

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Now this really goes back in history!

I bought my first Z3 (1.9) in '97 and it had a diff whine from the very first time I drove it on the highway

First, the Dealer replaced the diff with a new one off the shelf and that didn't fix the problem

Then BMW Aust ordered a new diff from the factory, the Dealer swapped it for the first replacement, it still whined

Then the rear end was completely dismantled and rebuilt including new everything plus stiffening, etc., and it still whined

Then a BMW Aust engineer fitted every sensor known to man to the car and spent almost a day in the car with me driving to accurately map my driving style, etc., had a new diff custom built in the factory, that was swapped for the second replacement, and it still whined

With diff builds and shipping times. etc., that took me to about 11 months after I bought the car and, with no other fix in sight and to keep me happy, the Dealer did a deal to trade up into a '98 2.8 at no cost to me with BMW Aust picking up the lease short-fall

I kept the '98 2.8 for almost 10 years and no diff whine or any other problem at all with that car, and the only reason I sold it was that I moved into a Townhouse with only 2 garages, had 3 cars, and something had to go!
 

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The Arkleyologist
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I posted a few weeks ago on this thread about the whine in my newly acquired 2000 Z3 coupe with 102K miles. I had my local mechanic swap the rear end with another one with 53K miles. It did not help as the whine was exactly the same. We reinstalled the original rear end, drained it, and put in the Amsoil 75-140. It made a huge positive difference in the noise levels. I can now drive the car without all that irritating noise. A big thumbs up for the Amsoil fix.
 

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Glad to hear that ZeeBoy.

I didn't change mine yet, because I can't find Amsoil or redline neither Mobil1 over here :S
All that I can find is the Mobil HD (Not synthetic) and Kraft fluids, I don't think they are good enough. I***8217;ll keep on searching... :(
 

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I'm 72 and serviced radios made before transistors came out. When a customer first noticed low frequency hum they would become fixated on the sound until it almost drove them nuts. From that day on all they listened for was the hum. Diff whine can also get on our nerves. My 2000 Z3 M whines a little.(24,000 miles) Maybe it's kinda like riding a Harley, just get louder mufflers. Harley's with stock factory mufflers clang and bang like an old wheat harvester. Put straight pipes on and she sings to you. Hard on other peoples ears tho. My point is just don't fixate on the noise it will drive you crazy and cost a lot to try to fix a built in defect. Sometimes we tune out our spouses why not diff noise? Bill
 
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