Hi guys,

I have had a minor driveline whine that I sort have ignored for a year or so. When exactly it started is not clear. As it has gotten colder this year it has (seemingly) been more noticeable, so it's time to investigate.

- whine stay the same in neutral or drive coasting
- whine is there with speed of wheels, whether coasting, accelerating
- it sort of sounds like an electric trolley (like the green line if you know boston)

- put car up on jackstands and listened underneath while assistant rev'd in Drive. Whine does not occur on jackstands
- checked diff fluid level - all is well (replaced 30k ago with Mobil1 75W-90)
- went for a drive and assistant drove so I could listen - sound is coming most prominently from the driveshaft center tunnel. Can't isolate to one side or the other.

This is a tough one - I have fully rebuilt the rear suspension on the vehicle (2 years ago) and I have replaced the center bearing on the driveshaft (3 years ago).

Any thoughts greatly appreciated. My hunch is the center bearing.Sorry for the long post -

dd

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'85 300D, 'Lance',250k, ... winter beater (100k on franken-Frybrid 3 Valve Kit)
'82 300D, 'Tex', 228k body / 170k engine ... summer car
'83 300TD Cali Wagon 210k, wife's car