I have the same problems that your are talking about. Except for the hard shifting. Mine isn't to bad but I have the backlash and noise coming from the tranny it seems like. I think it could also be something with the exaust because my cat makes a wierd buzzing noise sometimes at idle. I know it's the cat becuase it's very noticable when I have it running and I get underneath the car a little bit. It rattles and causes the noise, I think a little messing around with it will get it to stop buzzing. The noise from the tranny might not be related though. It's to hard to tell.
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Penz
1985.5 944
My 944 page