'99 WS; Trans bucking on 4th to 3rd downshift; anyone?

'99 WS LX 3.8L with 130,000 miles: When in 4th gear at low RPM's and usually going up a hill when a 4 to 3 down shift is needed, this WS will buck momentarily before actually downshifting. It almost feels like a mis-fire. Has anyone else experienced this? I use Mercon V and the level is a bit higher than it should be.

Yes, Does it all the time on my 99. Usually more in hotter weather. I'm in SE Penn so usually Spring and Summer - more and worse. They say it's the cluch/torque converter that causes the shudder. Like a mis-fire. It will get worse as time goes on, but my tranny still runs. Keep the fluid fresh and the level up to full. Not too much under or over.