A trailer includes a tongue, an upper frame, a lower frame coupled to the upper frame via a plurality of arms, and a lift assembly. The lift assembly includes 1) a hydraulic ram and 2) a hydraulic pump that is operatively connected to the hydraulic ram. The hydraulic ram raises the upper frame to a raised position when the hydraulic ram is retracted, and lowers the upper frame to a lowered position when the hydraulic ram is extended. The lift assembly is configured to be removably attachable to a trailer for retrofit operations, lift assembly replacement, or lift assembly reuse upon trailer sale or disposal. Also included is a method of raising and lowering a vehicle.