230 SL Rear Axle Noise

Several Months ago (perhaps a year) I noticed a swishing noise from my rear end, when under power. with the throttle backed off, there is no noise. This was most evident with the hard-top on, driving in city traffic.

Recently the noise became more evident and I had the drive shaft center bearing, rubber mounting and rear (transmission) mount replaced. This did not fix my problem and recently the noise became more pronounced and noticeable on the highway. The noise is difficult to describe, but sounds like a rubbing or swishing noise, but only occcurs under power. At times a vibration at + 60 MPH was evident, but not each time. Thinking it was a wheel bearing (and hoping it was not the pinion bearing) I jacked up the rear end until the tires cleared the ground, and found the right rear had clearance, allowing me to 'rattle' the tire up down and sideways. There was no motion on the left rear tire.

I pulled the left axle last night and the bearing (self centering roller type) appears good. No spaling is evident. When I reinserted the axle into the internal splines (of the right axle u-joint) I still get motion, allowing me to rock the axle flange. Is this normal? could it be that I do have a bad pinion bearing? I have no pinion seal leaks?

Opinions requested ASAP as my car is down. You can also call me @ (580) 255-6740.