1988 Silvia: Clutch or diff problems

[Ca_Silvia]

Everytime i shift in to a new gear the car seems to clunk (i know its a weak sauce description but there is a definate upset in the car) it only does it when i pull the clutch out to engage a new gear. Its not a grinding or slipping noise it kinda sounds/ feels like somehthing is loose and when i shift into the new gear it upsets the balance. It does not do it under braking/downshifting it only does it on acceleration. Now i also have an upgrade Cusco diff in the car aswell.

Is it possible this is the way the stage 2 clutch and diff work together and im just not used to it or is there someting wrong?

[navysnail]

grab the driveshaft and twist it back and forth while the car is in gear. see if it has much play. check your engine mounts too.