Shoot some WD around the base of the distributor and let it soak in.
I tend to agree with IC2, I had a clutch that had split in two
that also shudderd that way.
You are gonna have to pull the trany and inspect it.
We can guess all day and still have it wrong with out
seeing it. Is that trany is the one that the shifter is on the floor.
Or is it 3 on the tree or colum. Kurt