Yes, Transcendental meditation is quite similar to Mantra meditation. The main reason why transcendental meditation stands out from the rest is because of its mantra. The mantra you are asked to repeat during the meditation session empowers your whole process of transcendental meditation.
In transcendental meditation, the mantra that is repeated again and again is a sound that is said to be used as a vehicle to help your mind travel to a calm state and quiet mind and settle down.