wrd1972

iTrader: (12)

Okay I have the rhythmic noise from the rear at cruising speed that increase frequency as speed increases. I do have a MWC fab9 with adjustable TA and I also replaced the u-joints about a year ago.

Is this noise absolutely the result of DS angle? Or can it be attributed to joints as well? Seems like this just started out of nowhere with no other obvious red flags.

Thanks
Bill

Darth_V8r

iTrader: (4)

Does it change with a gear change? Does it change during acceleration or deceleration?

ssvert99

iTrader: (26)

Commonly referred to as "driveline drone". It is usually from imbalance of rotating parts, or a failed u joint, or improper angles causing harmonics. Rare occasion for something like a pinion bearing failure but not as common as driveline issues. Aluminum and carbon driveshafts tend to reduce the harmonics due to their increased critical speeds of the material.

wrd1972

iTrader: (12)

No gear change. Only when speeding up or slowing down.

Thanks Eric,
I will go under and check the DS angles.

Darth_V8r

iTrader: (4)

Typically driveline angles will present either when speeding up or slowing down. One would be better than the other. If you still have the steel driveshaft, going to aluminum will help by moving the harmonic frequency to a different speed range. Carbon fiber will move it even further.