thermal and hydrostatic effects in this closed system of interconnected reservoirs are fully compensated by a piston 62 that can be biased by belleville washers 64 for example or any other device that is comparable those skilled in the art will appreciate the benefit of such compensation on the structure of the device especially when it is deployed at great depths and or high temperature applications fig4 illustrates this execution of a compensation feature fig2 b best illustrates other features of this reservoir system there is a flow restrictor 66 that regulates the flow rate from reservoir 58 into reservoir 56 there is a check valve 68 that permits a bypass of restrictor 66 when the fluid is flowing in the opposite direction from reservoir 56 to reservoir 58 a pressure relief device 70 is in line with the restrictor 66 so that when fluid is urged in a direction from reservoir 58 to reservoir 56 there will have to be a rise in the driving pressure to cause such flow to a predetermined level before any flow begins broadly stated the fluid system is operative to create a delay as the dogs 24 are in the desired location and a force is applied to the mandrel 10 to create a surface signal for such engagement prior to the release of the dogs 24 from the locating groove not shown the system serves to allow a reduction of the applied pulling force before release to reduce the slingshot effect from release when used with the optional pressure relief device 70 the tool can be inverted and can be used to apply a load in a predetermined range on a bha without concern for premature release such as an offshore drilling application where a heave compensator.