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View Full Version : Differential noise = immanent death?


BennyM
08-26-2008, 04:19 PM
I haven't driven my 525i much this summer, and while it's sat the LSD has leaked most of it's fluid (though the leak probably started last year). As a result I now have wonderful whine on deceleration and a lovely clunk when I start from a standstill. I have always changed all other fluids on a fairly regular basis, but my dumb-ass neglected the differential. And now that the fluid is topped off, the noise remains. I know it's my fault, so no need to rail on me for that.

My question is: while I look for a new car should I also try to do a quick swap with a junkyard diff or can I keep driving it the way it is?

Reason for asking: I understand that a dead diff will lock up the wheels, stopping your car instantly. How likely is this to happen? Is this true only with open diffs? Has anyone heard of this actually happening?

I only planned on keeping the 5er a couple more months anyway.

BennyM
Ross
08-26-2008, 04:26 PM
Very unlikely for it to lock up, especially now that the fluid is topped off.
whiskychaser
08-26-2008, 04:51 PM
Running it without oil would make it whine but this doesnt sound like the case. You spotted the leak and I assume you didnt run it. Yeah top it off but be aware it could be something else - centre bearing or CV joint?
BennyM
08-26-2008, 05:07 PM
Running it without oil would make it whine but this doesnt sound like the case. You spotted the leak and I assume you didnt run it. Yeah top it off but be aware it could be something else - centre bearing or CV joint?

To clarify, The noise is definitely coming from within the diff.--Confirmed by myself and a mechanic. It was very low on fluid, not sure exactly, or for how long. I had not checked it for a long time. I saw no puddle under the car because it's parked on gravel, which also makes it a pain to get the car and look for seepage.
Ken35i
08-26-2008, 05:24 PM
Reason for asking: I understand that a dead diff will lock up the wheels, stopping your car instantly. How likely is this to happen? Is this true only with open diffs? Has anyone heard of this actually happening?

It's happened to a friend of mine He was doing 100km/h on a freeway and both his wheels suddenly locked up. He had recently changed from the stock viscous LSD to a 1.5way mechanical LSD. Though his diff was stuffed from the begining, not from a lack of oil over time. The main bearing was the culprit. His diff was siezed, of course, and it also buggered his clutch a bit. He managed to steer the car off the road.