An in-line jack includes a body, an extendable shaft, drive mechanics, and a motor. The body has first and second distal ends. The extendable shaft is movably disposed within the body and has a distal end extending out of the second distal end of the body. The drive mechanics are disposed within the body and are adapted to move the extendable shaft with respect to the body. The motor is mounted at the first distal end of the body and is adapted to selectively drive the drive mechanics. A coupling mechanism can be provided to selectively alternately couple: (i) a planetary gear system associated with the motor to a drive shaft of a jack screw assembly and (ii) a manual crankshaft to the drive shaft to operate the jack manually. The body and the motor each has a generally cylindrical outer surface with an outer diameter equal to or less than about three inches. The body, the jack screw assembly, the coupling mechanism, the planetary gear system, and the motor are substantially axially aligned with each other.