A colocated multiple-input multiple-output (MIMO) radar transmit scheme is introduced which trades off waveform diversity with beampattern directivity through the use of a linear precoder. Time-division beamforming defines a transmit signal where beamforming vectors are temporally multiplexed throughout a single pulse. The beamforming vectors provide direct control of the transmit beampattern, able to form multiple transmit beams in a single pulse. The MIMO receive ambiguity function, which incorporates the receiver structure, reveals a space and delay-Doppler separability that emphasizes the importance of the transmit-receive beampattern and single-input single-output (SISO) ambiguity function. We introduce a max-min signal-to-interference plus noise ratio (SINR) optimization to design the time-division beamforming signal in a multiple target scenario given target location estimates. Results are compared with existing MIMO radar transmit schemes, under the assumption of both perfect and imperfect target location estimates.