Drive shaft center bearing

[Kneale Brownson]

I'd agree.  My wife's 4kq does this about once a year:  tired muffler 
"donuts".  They haven't ripped yet, but they're stretched enough the 
exhaust starts thumping on something if you decelerate in gear.


At 11:14 AM 10/12/2001 -0400, Doyt W. Echelberger wrote:

>Hello Dennis.............When my center bearing failed, it squealed and 
>shrieked, metal on metal, under load. I could put it in first and 
>accelerate and the shriek got really loud. The drive shaft was turning and 
>the bearing wasn't. The faster the shaft turned, the louder the sound. 
>Yours is just the reverse, regarding the things that make it happen.
>
>"Rumbling and vibration"  sound more to me like heavier masses being 
>involved. Or better yet, an exhaust pipe rubbing against a turning drive 
>shaft. When you let up on the accelerator, the motor mounts and tranny 
>mounts allow the engine to change position on its longitudinal axis, and 
>the exhaust pipe moves like a lever in this situation, and may be twisting 
>over and touching the drive shaft at some point.
>
>There isn't much pressure on that center driveshaft bearing, and the mass 
>of the bearing itself is insignificant. It is suspended in the center of a 
>rubber panel, which allows it to move with some "give."  Difficult to 
>imagine it rumbling.
>
>Rumbling would imply several heavy masses bouncing along on each other. 
>Like an exhaust pipe and a driveshaft.
>
>Just my opinion, if I had to guess. Look for clearances between these two 
>things, and look for evidence of contact. You may have a soft tranny mount 
>that is allowing the power train to shift  beyond expected limits.    Doyt 
>Echelberger  87 5ktq
>
>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>.
>At 09:27 AM 10/12/2001 -0400, you wrote:
>>What is the symptom of a center bearing going south?
>>I have a vibration/rumbling on slight deceleration. Not under load, and 
>>not when coasting with the clutch in, and not at +50mph. Does that sound 
>>like a center bearing, or carrier?
>>If so, which BMW unit crosses over? Please save me an hour searching the 
>>archives.
>>
>>Dennis
>>Denver
>
>
>