A tractor-loader-backhoe is disclosed wherein the loader mechanism is mounted on the frame of the prime mover by a tapered pivot pin having a fastener extending entirely through the axis of the pivot pin to effect a clamping load operable to seat the tapered pivoted in the conical hub affixed to the frame of the prime mover to assure a firm fastening of the loader mechanism on the prime mover. The backhoe mechanism is provided with a transport lock remotely accuatable from the operator's cab mounted on the prime mover and incorporating a locking pin having a concentric spring mounted thereon to urge the pin out of engagement with the frame whenever the transport lock is disengaged to permit operation of the backhoe mechanism. The boom and dipper members of the backhoe mechanism are constructed from a pair of opposing C-shaped channels having inwardly directed legs centrally located within the boom and dipper members. The opposingly facing channel members form a longitudinally extending seam to facilitate welding of the two channel members constructing the boom and dipper members.