I had a problem with the driveshaft causing a thumping sound under acceleration. I could move the shaft about a quarter inch within the support bearing and duplicate the thumping sound. So I replaced both the driveshaft support and the bearing, being careful to ensure that I marked all relative positions so I didn’t install it out of phase.

When I test drove the car, the thumping sound was cured. But now the driveshaft shudders when accelerating from a standing start. It doesn’t shudder any other time, even when accelerating at speed or going up a hill. Once I get going, it smooths out.

I’m wondering if there’s some critical adjustment I need to make to ensure alignment There’s a spline joint that I had to take apart to get the bearing off. The spline pieces went together and are held in place by a set screw. The slack is taken up by the drive shaft flange at the transmission, which has some float or play. I put all the pieces back exactly as they came off.

Could I have installed the bearing crooked? Or do I need to follow some procedure to readjust the spline or location of the support assembly?

I’m at wit’s end and would appreciate any advice!

Robert