Driveshaft clunking when pulling away. Flex disc and cs bearing shot?

[Chris_D]

So the zed only gets a weekly runabout exercise atm as i have a lovely client-supplied skoda as a daily.
However, the last couple of times, esp when topdown, ive noticed a clunking sound coming from underneath the car, possibly towards the rear when changing through 2nd to 3rd gear, also to 4th at low speed.
I'm presuming at the stage that its the propshaft flex disc and/or centre support bearing as it seems to be a common issue on high mile beemers. Could also be diff input bearing perhaps. Don't have any perceptible vibrations at any speeds, just a clanking noise when pulling away.
I'm currently on 110k and just changed gearbox and diff oil. Didnt inspect the flexdisc while i was under there sadly.

I know the following vid is for a z3 but i'm assuming the prop setup is similar for most bmw's. Could this be my issue? Anyone had similar symptoms / issues / noises?

[Ducklakeview]

Chris, your car is a manual isn't it? The "flex disc" is only fitted the the autos, it fixes the torque converter to the crank. My Zed doesn't have those rubber donuts in it's driveline. Could be the top rear diff mounting bush..

Mike

[Chris_D]

Chris, your car is a manual isn't it? The "flex disc" is only fitted the the autos, it fixes the torque converter to the crank. My Zed doesn't have those rubber donuts in it's driveline. Could be the top rear diff mounting bush..

Mike

aah reet. yep it's a manual. thought manuals had this too. weird.
will take a butchers at diff mounts - saw a vid on those too where there was excessive movement of the diff when changing up thru the gears and causing a clanking noise. bushes were shot

[GuidoK]

Chris, your car is a manual isn't it? The "flex disc" is only fitted the the autos, it fixes the torque converter to the crank. My Zed doesn't have those rubber donuts in it's driveline. Could be the top rear diff mounting bush..

Mike

I'm pretty certain your car also has a flex disc/hardy disc

A worn flex disc or center bearing on the propshaft can definatly give a clunking noise when pulling away or on on-off-on throttle.
But so could a worn rear diff bushing.
The flex disc and center bearing are not easy to inspect/replace because the exhaust&heat shielding have to come off before you can see/replace them.

[Ducklakeview]

Chris, your car is a manual isn't it? The "flex disc" is only fitted the the autos, it fixes the torque converter to the crank. My Zed doesn't have those rubber donuts in it's driveline. Could be the top rear diff mounting bush..

Mike

I'm pretty certain your car also has a flex disc/hardy disc

No, it has a dual mass flywheel.

Mike

[GuidoK]

^yes I know it has a dual mass flywheel.
But the flex disc/hardy disc is located on the other side of the gearbox. It forms the connection between the propshaft and the output shaft from the gearbox.
You're probably confused with the driving plate to which the torque converter bolts to.

I'm positive that the manual has a flex disc. I had it in my hand probably more than 10 times

[Roundozo]

Manuals do have the doughnut (flexible disk). I changed mine last year. Wasn't that worn at 90k but while I was changing the clutch it made sense.

[Chris_D]

Chris, your car is a manual isn't it? The "flex disc" is only fitted the the autos, it fixes the torque converter to the crank. My Zed doesn't have those rubber donuts in it's driveline. Could be the top rear diff mounting bush..

Mike

I'm pretty certain your car also has a flex disc/hardy disc

A worn flex disc or center bearing on the propshaft can definatly give a clunking noise when pulling away or on on-off-on throttle.
But so could a worn rear diff bushing.
The flex disc and center bearing are not easy to inspect/replace because the exhaust&heat shielding have to come off before you can see/replace them.

Thanks Guido, I thought that was the case but I know Mike is a decent enough tinkerer and might have been correct. Mike, it's the 'Universal Joint' or rubber 'Guibo' connecting interface, sometimes referred to as 'doughnut' that dampens the torque between the prop-shaft output and the diff input. Supported by a separate 'Centre Support bearing'. Items 1 and 8 at realoem.com:

http://www.realoem.com/bmw/enUS/showpar ... Id=26_0193

So 2 things to check, 1st the diff mountings as it's easier to inspect/rectify, then UJ'doughnut' & CS bearing. Concur?

[MACK]

Can confirm us manual owners have the rubber donut. Chris this could be the clunk that is fixed with a type of paste put onto the splines of the shaft to take up a minute amount of play. I did this fix myself when I got mine, same symptoms a clunk when first moving off. There are some thread on here I think and certainly over BMW forums regarding this. I think the paste is Loctite 660 liquid metal. You can buy it a t BMW but its cheaper elsewhere (surprise, surprise!)

[Smartbear]

my manual si had the propshaft donut as well
Rob

[Ducklakeview]

Chris, your car is a manual isn't it? The "flex disc" is only fitted the the autos, it fixes the torque converter to the crank. My Zed doesn't have those rubber donuts in it's driveline. Could be the top rear diff mounting bush..

Mike

I'm pretty certain your car also has a flex disc/hardy disc

A worn flex disc or center bearing on the propshaft can definatly give a clunking noise when pulling away or on on-off-on throttle.
But so could a worn rear diff bushing.
The flex disc and center bearing are not easy to inspect/replace because the exhaust&heat shielding have to come off before you can see/replace them.

Thanks Guido, I thought that was the case but I know Mike is a decent enough tinkerer and might have been correct. Mike, it's the 'Universal Joint' or rubber 'Guibo' connecting interface, sometimes referred to as 'doughnut' that dampens the torque between the prop-shaft output and the diff input. Supported by a separate 'Centre Support bearing'. Items 1 and 8 at realoem.com:

http://www.realoem.com/bmw/enUS/showpar ... Id=26_0193

So 2 things to check, 1st the diff mountings as it's easier to inspect/rectify, then UJ'doughnut' & CS bearing. Concur?

Never heard of or seen a manual with a flex plate...

Mike

[Smartbear]

our previous z3 2.2 had one as well
Rob

[Chris_D]

I'm pretty certain your car also has a flex disc/hardy disc

A worn flex disc or center bearing on the propshaft can definatly give a clunking noise when pulling away or on on-off-on throttle.
But so could a worn rear diff bushing.
The flex disc and center bearing are not easy to inspect/replace because the exhaust&heat shielding have to come off before you can see/replace them.

Thanks Guido, I thought that was the case but I know Mike is a decent enough tinkerer and might have been correct. Mike, it's the 'Universal Joint' or rubber 'Guibo' connecting interface, sometimes referred to as 'doughnut' that dampens the torque between the prop-shaft output and the diff input. Supported by a separate 'Centre Support bearing'. Items 1 and 8 at realoem.com:

http://www.realoem.com/bmw/enUS/showpar ... Id=26_0193

So 2 things to check, 1st the diff mountings as it's easier to inspect/rectify, then UJ'doughnut' & CS bearing. Concur?

Never heard of or seen a manual with a flex plate...

Mike

Flex 'disc' mike, not plate. easy to associate with auto gearbox but in this case it's part of the propshaft. av a butchers at that realoem link and all shall become patently clear

[mmm-five]

Mine's just been replaced on the M, and I've had a couple on previous (all manual) M cars.

Weirdly, only just realised that the Z4MC one is the same as the e34 m5 one

You can even get 'upgraded' ones...

...but I've never bothered as I prefer to keep the sacrificial part repairs in the hundreds (guibo) rather than the thousands (diff, gearbox, clutch, flywheel).

[Chris_D]

Mine's just been replaced on the M, and I've had a couple on previous (all manual) M cars.

Weirdly, only just realised that the Z4MC one is the same as the e34 m5 one

You can even get 'upgraded' ones...

...but I've never bothered as I prefer to keep the sacrificial part repairs in the hundreds (guibo) rather than the thousands (diff, gearbox, clutch, flywheel).

Bloody hell! That old one is proper shot to pieces!
Wondering now if a failure, and yours looks close to catastrophic failure, would cause greater problems in the driveline. Can imagine a de-linkage perhaps, maybe the prop coming loose and dragging. Could coming off-centre have disastrous consequences? I suppose you'd hear it go kerplup and have time to react accordingly.
Wow, I think you caught that just in time fella!