A fluid coupling device of the type including a first rotatable coupling member defining an axis of rotation, enclosure means associated with said first coupling member to define a fluid chamber therebetween; valve means disposed to separate said fluid chamber into a fluid operating chamber and a fluid reservoir chamber; a second rotatable coupling member disposed in said fluid operating chamber and being rotatable relative to said first coupling member, at least one of said first coupling member and said enclosure means cooperating with said second coupling member to define therebetween a viscous shear space; said valve means being operable to control the flow of fluid between said reservoir chamber and said operating chamber, and including control means (47, 55) associated with said valve means to effect the operation thereof in response to variations in a predetermined condition; said valve means including a plate-like member defining a fluid inlet port disposed to permit fluid flow from said reservoir chamber to said operating chamber, said valve means further including a moveable valve member operably associated with said control means (47, 55): wherein: (a) said plate-like member defines a first inlet port, and a second inlet port disposed radially outward of said first inlet port; (b) said moveable valve member has a disengaged position (FIG. 4) blocking flow through both said first and second inlet ports; (c) said valve member is configured such that, as said valve member moves from said disengaged position, toward a first operating position (FIG. 5), said first inlet port is uncovered while said second inlet port remains covered; and (d) as said valve member moves from said first operating position (FIG. 5) toward a second operating position, said second inlet port is progressively uncovered; characterised in that: (e) said second rotatable coupling member includes said plate-like member, and an additional enclosure means cooperating with said plate-like member to define said fluid reservoir chamber, whereby said fluid reservoir chamber rotates at the speed of rotation of said second rotatable coupling member, and in that said plate-like member defines a first, transverse surface defining said first inlet port, and a second, cylindrical surface defining said second inlet port, said valve member defines a first, transverse surface disposed to block fluid flow through said first inlet port when said valve member is in said disengaged position (FIG. 4), said valve member further defines a second, cylindrical surface in sliding engagement with said second, cylindrical surface of said plate-like member, as said valve member moves from said disengaged position (FIG. 4) toward said first operating position (FIG. 5). (a) said plate-like member defines a first inlet port, and a second inlet port disposed radially outward of said first inlet port; (b) said moveable valve member has a disengaged position (FIG. 4) blocking flow through both said first and second inlet ports; (c) said valve member is configured such that, as said valve member moves from said disengaged position, toward a first operating position (FIG. 5), said first inlet port is uncovered while said second inlet port remains covered; and (d) as said valve member moves from said first operating position (FIG. 5) toward a second operating position, said second inlet port is progressively uncovered; characterised in that: (e) said second rotatable coupling member includes said plate-like member, and an additional enclosure means cooperating with said plate-like member to define said fluid reservoir chamber, whereby said fluid reservoir chamber rotates at the speed of rotation of said second rotatable coupling member, and in that said plate-like member defines a first, transverse surface defining said first inlet port, and a second, cylindrical surface defining said second inlet port, said valve member defines a first, transverse surface disposed to block fluid flow through said first inlet port when said valve member is in said disengaged position (FIG. 4), said valve member further defines a second, cylindrical surface in sliding engagement with said second, cylindrical surface of said plate-like member, as said valve member moves from said disengaged position (FIG. 4) toward said first operating position (FIG. 5).