No noise, just a low frequency vibration through the body.. Noticed it a few days ago at about 70mph. Now noticeable at 50-60mph. Would I be correct in assuming it could indicate the guibo or rubber u/j on the propshaft is failing? Cars done about 170k. TIA. Mike.
Maybe the wheels need balancing. Fronts are easy to tell because of the steering vibration, but rears you usually feel through the seat base.
Wheel bearing?
It's hard to diagnose noises without driving the vehicle.
Could be Wheel balancing or Rotors.
Does he happen more when brakeing?
-Branden
I'm sure it's not either of those. Definitely feels more like something in the transmission, rather than anything to do with the wheels or discs. Although it's quite noticeable to me as the driver, I doubt a passenger would notice it.
No. The vibration seems to be independant of brakes or throttle setting. That's what leads me to believe the propshaft being out of balance is the culprit. I can get underneath it at the weekend, and check it. Just wondered if my suspicion was correct. Had a u/j fail on a car many years ago. It feels very similar. Out of interest, what are the symptons of a failing Guibo? Mike.
"Mike G" wrote
The others have suggested some things. Have you carefully inspected the tires to ensure you don't have a tread separation - especially on the rears since it seems to be associated with the driveline?
FloydR
it could be a lot of things, mostly tires, but if it's smooth as glass at lower speeds and sersiously lumpy around 60 then yeah, I'd think it was the rubber flex coupling.
All good suggestions, but I'm certain that it's a mechanical fault rather than one caused by unbalanced or damaged wheels tyres or rotors. The tyres all round are nearly new ContiSport Contacts, on near perfect BMW wheels. I'll have a crawl around underneath at the weekend. Check the drive train etc. Mike.
I'm sure you're right. I'm 99.9% it's not tyres. As I said though. I should know at the weekend when I check the drive train. Mike.
So long as you're 100% absolutely certain that there's no possibility at all that a wheel balance weight has come off without you knowing, or that one of your new tyres has developed a defect, or that one of the wheels or tyres was knocked while you weren't looking, then by all means go ahead and dismantle the drivetrain to see if it's damaged. If the drive train's OK, then the next step will be to take it to a really good body shop to make sure that the frame isn't bent. If all that checks out OK, then maybe you should look at the wheels and tyres, and maybe the brake rotors. Let us know what happens.
Have you ever heard of Occam's razor?
I should have added that the vibration feels like the wrong frequency for it to be wheel balance problem. Much higher than the wheel rotation speed. Nearer propshaft rotation speed IMO, which is why I think the propshaft might be out of balance, due to a failing Guibo or u/j.
then by all
I don't intend to strip anything down at the weekend. If the Guibo, or centre u/j is failing it should be evident from a visual inspection.
then the next step will be to take it to a
It's nothing to do with the body. It's definitely a balance problem. I'm not that familiar with the E39 yet, I've only had it a couple og months, but I do know what a failing u/j on a propshaft feels like, and this feels very similar, but the E39 propshaft is an odd combination of flexible 'u/j', or Guibo, Hardy Spicer type u/j and a CV joint, so theoretically it could be any one of them. Or it could be something as simple as a balance weight falling off the propshaft itself.
If all
I'll do that.
Yes, which is why I'm looking at the most likely, and a fairly easy place first.:-) Mike.
My direct experience with a drive shaft balance problem (it was on an E34) was that the primary vibrations began at a much lower speed (like around 25-30 mph). I believe that this is because the shaft turns much faster than the axles and wheels due to the final drive gears / ratio.
From 35-50 would be smooth and a secondary (harmonic) vibration would occur at around 55-65 which would also then smooth out at around 75-80 mph.
Vibration that initially occurs at 55-60 mph should be something after the differential. On the same car as above I had some crappy Continental Extreme contact tires that would flat spot every morning. The car would vibrate every morning in the 55-65 mph range until those tires completely warmed up.
It could also be a warped brake rotor. Try jacking each corner and spinning each wheel and feel for constant resistance from the brake pads (not being applied).
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