tool 10 or any portion thereof additionally since the wellsite operation may be continued even after one of the pressure relief devices 36 64 has opened the shear members 88 may be sized to release the sleeve 86 at a differential pressure the same as greater than or less than that at which the shear members 72 release the plug 60 for displacement relative to the crossover housing 48 note that the sidewall portion of the housing 82 through which the passages 84 are formed is a pressure bearing wall of the assembly 30 exposed on its interior to fluid pressure in the fluid return flowpath 62 and on its exterior to fluid pressure in the fluid delivery flowpath 56 therefore when the sleeve 86 is displaced relative to the housing 82 and fluid flow is permitted through the passages 84 the difference in fluid pressure between the fluid delivers and return flowpaths 56 62 is substantially immediately relieved thus has been described the tool 10 including the pressure relief devices 36 64 incorporated therein which operate to protect the tool from harmful differential pressures between fluid delivery and return flowpaths 56 62 thereof of course many modifications additions substitutions deletions and other changes may be made to the exemplary embodiment of the invention described above which changes would be obvious to one of ordinary skill in the art for example the filtering devices 78 90 could be otherwise configured or eliminated.