My 2008 3.0i has a tendency to make a light clunking sound from about the rear diff area about 25% of the time when letting in the clutch or letting out the clutch and changing into a higher gear. Sometimes it's hard enough to feel it slightly. I could see there being some play between things but not sure... Anyone else have this or should I take it in before the warranty expires in June?
Rear end clunk?
- Thread starter chjade84
- Start date
I am sure one or two people have had drive shaft issues, but that's about it, as far as I remember.
However, I'd get it straight into the dealer to look at under warranty anyway - silly to have one and not make the most of it
At the very least you will get the problem logged - if they say there is nothing wrong and something fails or gets a lot worse soon after June you may have a chance of getting it done under goodwill. I did on something with mine.
However, I'd get it straight into the dealer to look at under warranty anyway - silly to have one and not make the most of it
At the very least you will get the problem logged - if they say there is nothing wrong and something fails or gets a lot worse soon after June you may have a chance of getting it done under goodwill. I did on something with mine.
If it's the same problem others have had, there's a short flanged and splined shaft connecting the prop shaft to the pinion gear. It tends to slam against the diff case bulkhead carrying the pinion seal. Applying a bunch of grease to the end of the splined shaft softens the impact and attenuates the noise.
So I took it in and of course they "couldn't duplicate the problem". He did let it slip that they guy drove it through the business park but didn't even take it out on the roads - when I said it seems to happen mostly when you are "exercising" the car a bit. Of course you can't duplicate it being gentle in a parking lot! :headbang:
He did say that I could come back and take the tech for a ride and show him myself. I think I've devised a sure-fire way to make it happen. It seems downshifting from 5th or 6th to 4th doing about 60mph without matching revs perfectly makes it happen the most dramatically - most of the time... But really downshifting at any time with the engine revs lower than the wheel revs will cause it to clunk and of course lurch a bit. The lurching I'm fine with as that is what happens when the wheels are connected to an engine spinning slower than they are but is the corresponding clunk also normal? It does seem to happen about 50% of the time. The other 50% it feels as I imagine it should, no metallic clunk just the car slows dramatically as the engine catches up to the wheels.
EDIT: I should mention I'm not just dumping the clutch in 4th gear on a near idle engine doing 60mph. If it's under the correct engine speed for 4th gear @ 60mph by about 500RPM or so this will happen - not so often if you over-rev.
He did say that I could come back and take the tech for a ride and show him myself. I think I've devised a sure-fire way to make it happen. It seems downshifting from 5th or 6th to 4th doing about 60mph without matching revs perfectly makes it happen the most dramatically - most of the time... But really downshifting at any time with the engine revs lower than the wheel revs will cause it to clunk and of course lurch a bit. The lurching I'm fine with as that is what happens when the wheels are connected to an engine spinning slower than they are but is the corresponding clunk also normal? It does seem to happen about 50% of the time. The other 50% it feels as I imagine it should, no metallic clunk just the car slows dramatically as the engine catches up to the wheels.
EDIT: I should mention I'm not just dumping the clutch in 4th gear on a near idle engine doing 60mph. If it's under the correct engine speed for 4th gear @ 60mph by about 500RPM or so this will happen - not so often if you over-rev.
bcworkz said:Maybe you should learn to rev match better?oke:
I do understand the difference between happening intermittently and forcing it to happen. Just couldn't resist. :evil:
It's kind of unnerving when I get a perfect rev match. Every time it happens I either think the clutch has gone or something has come apart!
Well I took it in last Friday and took the guy for a drive. OF COURSE it didn't act up as much as normal... :headbang:
I did get a few clunks out of it and the tech said it sounded like the drivetrain moving around in the bushings. He said he inspected them last time and they look good for 30,000 miles and don't need replacement. He suggested I let the clutch slip some more when downshifting especially to put less strain on the drivetrain and keep things from moving as much. That does help but I still notice all kinds of clunks and thumps from the rear end during normal driving. Sometimes just letting the clutch in whilst coming to a stop, other times little clunks while letting the clutch slip out into gear upshifting. The tech said it's because of how tight everything is in a BMW - that power will move things around.
Does anyone else get this kind of thing while driving? Maybe I'm just expecting more from my first BMW. It WAS built here in America though... maybe that's why Germany brought assembly back with the new body style...
I did get a few clunks out of it and the tech said it sounded like the drivetrain moving around in the bushings. He said he inspected them last time and they look good for 30,000 miles and don't need replacement. He suggested I let the clutch slip some more when downshifting especially to put less strain on the drivetrain and keep things from moving as much. That does help but I still notice all kinds of clunks and thumps from the rear end during normal driving. Sometimes just letting the clutch in whilst coming to a stop, other times little clunks while letting the clutch slip out into gear upshifting. The tech said it's because of how tight everything is in a BMW - that power will move things around.
Does anyone else get this kind of thing while driving? Maybe I'm just expecting more from my first BMW. It WAS built here in America though... maybe that's why Germany brought assembly back with the new body style...
I have exactly the same thing on mine. noticeable when moving slowly in traffic, pushing the clutch in when in first gear. also when reversing up my drive on a slight hill, when letting the clutch out.
I had the flange grease thing done, but it didnt fix it, dont want to spend a fortune getting mechanics to keep looking at it so once the weather gets better Im going to get it jacked up and see if I can see anything myself.
If you do get to the bottom of it please let me know what it was!
I had the flange grease thing done, but it didnt fix it, dont want to spend a fortune getting mechanics to keep looking at it so once the weather gets better Im going to get it jacked up and see if I can see anything myself.
If you do get to the bottom of it please let me know what it was!
gazrobbo said:
As I said in an earlier post a while back, most of my clunking was coming from the drive shaft where the two sections are splined together. My Indie dismantled the drive shaft and reassembled it with a ton of silicon in the grooves of the splines...he said he had performed this many times before and it should be a permanent solution. It was just some wear on the splines.
With the car on the rack, you can leave it in gear and turn the rear wheels back and forth. It will be very easy to determine where the noise is coming from. I was under the car when we did this and I was totally surprised to hear it coming from the drive shaft joint when I expected the clunk clunk to be at the diff flange. Sitting in the car it sounded like the noise was coming from the differential area.
Just lift the car and check it out...you will have to drop the exhaust and the covers to pull the drive shaft for a fix.
