A modular connection system (4y;1000;1 100;1200;1300;1400), comprising: a first tubular (31d,c,s;1010;1110;1210;1310;1410) configured to connect to a top drive, wherein the first tubular has a first bore (1013;1214) therethrough and a load transfer feature (31sh;1012;1112;1211,1212;1312;1411) formed on an outer surface, and the first tubular comprises: a first coupler (1041;1135) for transferring at least one of hydraulic power, electrical power, pneumatic signal, data, and electrical signal; and a second tubular (36;1020;1120;1220;1320;1420) configured to connect to a tool, wherein the second tubular has a second bore (1023;1123;1223;1423) and a cavity (1031;1131;1321;1437) for receiving the first tubular, and the second tubular comprises: a second coupler (1035;1141) for transferring at least one of hydraulic power, electrical power, pneumatic signal, data, and electrical signal; and a locking element (38b;1025;1140;1230;1322;1425) movably disposed in the cavity between a first position and a second position, wherein when the locking element is in the first position, the first tubular is insertable to the cavity so that the first coupler is coupled to the second coupler and the first bore is connected to the second bore, and when the locking element is in the second position, the load transfer feature engages the second tubular to transfer axial loads and torsional loads between the first and second tubulars. a first tubular (31d,c,s;1010;1110;1210;1310;1410) configured to connect to a top drive, wherein the first tubular has a first bore (1013;1214) therethrough and a load transfer feature (31sh;1012;1112;1211,1212;1312;1411) formed on an outer surface, and the first tubular comprises: a first coupler (1041;1135) for transferring at least one of hydraulic power, electrical power, pneumatic signal, data, and electrical signal; and a second tubular (36;1020;1120;1220;1320;1420) configured to connect to a tool, wherein the second tubular has a second bore (1023;1123;1223;1423) and a cavity (1031;1131;1321;1437) for receiving the first tubular, and the second tubular comprises: a second coupler (1035;1141) for transferring at least one of hydraulic power, electrical power, pneumatic signal, data, and electrical signal; and a locking element (38b;1025;1140;1230;1322;1425) movably disposed in the cavity between a first position and a second position, wherein when the locking element is in the first position, the first tubular is insertable to the cavity so that the first coupler is coupled to the second coupler and the first bore is connected to the second bore, and when the locking element is in the second position, the load transfer feature engages the second tubular to transfer axial loads and torsional loads between the first and second tubulars. a second coupler (1035;1141) for transferring at least one of hydraulic power, electrical power, pneumatic signal, data, and electrical signal; and a locking element (38b;1025;1140;1230;1322;1425) movably disposed in the cavity between a first position and a second position, wherein when the locking element is in the first position, the first tubular is insertable to the cavity so that the first coupler is coupled to the second coupler and the first bore is connected to the second bore, and when the locking element is in the second position, the load transfer feature engages the second tubular to transfer axial loads and torsional loads between the first and second tubulars.