Yeah, I've visited David before - pretty knowledgeable guy. Good suggestion; he might know a source.

Larry, I started to send you a msg. I remember your experience with the center bearing.
Mine has had a slight shudder when accelerating off in 2nd gear, only between 15-17 MPH. Done it for 5 years.
But, lately it seems to be getting worse; noticeble during each start, and really noticeable if accelerating up hill at the 15-17 MPH window.
It normally lasts only a couple of seconds, longer if going uphill. Shakes the car pretty good; feels to be driveshaft speed.
Smooth as silk at cruising speeds.
From the time I first noticed it, I have replaced the front flex, the center bearing, the tranny and dif mounts, and inspected and switched the rear axles L to R. I also tried repositioning the center bracket as you suggested; all with no improvement.
Last time I had the shaft out - several years ago - I definitely had the "detent" in the u joint. It wasn't too bad, but if it had been replaceable I definitely would have done it back then.

I'm gonna go back in and check everything; but since I replaced most of the stuff over the years with no change, I'm kinda assuming I just didn't hit the right part, and it's slowly getting worse. And the only part left I can think of is the U joint. The rear flex is original !!!! but it looks & feels fine.

One last caveat: last night I swear I felt the shudder in 3rd gear, at the same RPM as it's always occurred in 2nd. If that's the case, it's likely in the tranny or torque converter. Man, I hope not. But if it continues to deterioate, I guess I'll find the sneaky devil easier.

Ever heard of a non-lockup converter going out?

DG