I just swapped a 98 GSR into my 96 Coupe. When I let go of the clutch, I feel a knocking sound and I can feel the car pull slightly. If I let out the clutch really slowly, it doesn't do it. If I let it out at a normal speed it knocks. It's not really loud, but it's enough to piss me off. It does it when I go into reverse as well. When I'm rolling, if my timing isn't perfect when switching from the clutch to the gas, I'll hear it a bit too (I can also feel it a bit, but not as much as when my car is still). It seems to do it with the lower gears than higher.
I don't get it, the axle are new (well technically they are newly rebuilt). Might it have to do with the axles. It gives me the impression that there migfht be some play in the axle, and the knocking happens when it grabs properly.

Any help or info would be appreciated. Oh BTW I searched, and I really didn't find any info. I found one post and I IM the guy who started the thread and didn't get a response.