Anyone know what a driveshaft coupling does?!

[Chilli]

Any advice would be appreciated.
I'm experiencing a small shake on the wheel, and at certain speeds (about 60) I can only describe the feeling as if not all the wheels are perfectly round! I bit of vibration and a wobble, together with excess road noise. I've taken it into a BMW specialist, but they accept there is something wrong, but don't know what it is. They say it MIGHT be the steering rack. The car is a BMW X5, 4.8.
I suggested the driveshaft coupling, as the back street garage that tested it (when I bought it), suggested this would need replacing...they are a testing station here in Dubai, and to them an MOT is to kick the tyres).

Any thoughts or experiences?

Cheers.

[Kevin VRs]

Have you tried balancing the wheels/tyres? This can cause vibration at certain speeds. Also that the tyres are correctly fitted to the rims, one may be out of true thus becoming 'not round'.

[dugt]

You could try swapping the front wheels for the back wheels, (assuming they are the same size) to see if it gets any better or worse

Youve got nothing to loose by doing it and it will be free.

[ymwoods]

Could be that the wheels need balancing or the diff could be going or the steering rack. Could also be a bent driveshaft...but you would know if you had bent it as you would have had to give it one hell of a smack. Not too sure about a driveshaft coupling though...

[Chilli]

Na the wheels have been balanced....that was my initial thought. Also the rear wheels are much bigger than the front, so that's a no go.
I remember this "2-bit" garage putting it in drive, hard on the brakes, and pressing the gas pedel. they did this a couple of times....I'm wondering if they knew it would cause this and therefore felt like an expert by saying this coupling thing would need replacing.
I would just take it into the local stealers, but given they tried to rape me last month, I'd rather tell the indy what it is...funny eh?!

[stewy68]

As above, swap front to back and see what happens. buckled driveshaft is unlikely IMO, as this would surely show up at different speeds. Can you drive through it (ie. is it still the same above 60)?
After swapping wheels, get the balance checked and at same time make sure the rims are not dented or buckled causing tyre distortion.

[Rich_W]

A driveshaft coupling is the name sometimes given to the Universal Joint about half way down the prop shaft. I don't know specifically on X5's but on 3 and 5 series it's a rubber "guibo" which over time can wear and cause a vibration as the prop rotates and isn't held in the same postion.

http://www.realoem.com/bmw/showparts.do?model=FF41...

Part 1.

Alternatively, Part 7 could also be responsible for you noise.

[Chilli]

Rich_W said:

A driveshaft coupling is the name sometimes given to the Universal Joint about half way down the prop shaft. I don't know specifically on X5's but on 3 and 5 series it's a rubber "guibo" which over time can wear and cause a vibration as the prop rotates and isn't held in the same postion.

http://www.realoem.com/bmw/showparts.do?model=FF41...

Part 1.

Alternatively, Part 7 could also be responsible for you noise.

That's excellent, I'll forward that info on.

Many thanks for your time.

[Eggman]

Is there a flexible coupling where the front prop enters the diff? If not, you might have wear in the splines at that point and I can imagine you might feel that through the wheel. I think there was some kind of recall for it - the problem affects Range Rovers too. I expect your '2 bit' garage was listening for clonks using their special mechanics' ears.

[Chilli]

Eggman said:

Is there a flexible coupling where the front prop enters the diff? If not, you might have wear in the splines at that point and I can imagine you might feel that through the wheel. I think there was some kind of recall for it - the problem affects Range Rovers too. I expect your '2 bit' garage was listening for clonks using their special mechanics' ears.

No idea, but I'll forward this on.
Thanks mate.

[davemac250]

Hi.

Couple of things.

Wheel balancing only works up to the speed the machine can spin the wheel at. After that it all gets a bit hit and miss. (Just had a wheel that was impossible to balance properly - any speed abobe 60mph the vibrations started then just kept building) Try swapping in a new wheel to see what happens.

Sounds daft, but get the garage to check the wheels are round on the inner rim. The wheels are so deep on X5/Cayenne/Touaregs/RRS the inner rim can warp as there is little strength there.

Failing that, you sre down to the UJ's and transfer boxes.

[TITWONK]

worth checking the rim is sitting nice and true on the hub, get a wire brush and clean both the wheel and hubs surface.