 The differences are the bell housing bolt pattern and the output shaft flange with a 3-bolt flange for the redblock/diesel engines and a 4 bolt flange for whiteblock engines.The variant for the 6-cylinder Volvo engine will fit on all 4/5/6 all-aluminum Volvo N/RN-series engines.The clutch is hydraulically operated by a master/slave cylinder setup with a normal clutch fork and throw out bearing.