Depending on whether your vehicle is an automatic or manual transmission, there are different signs to be on the lookout for that can mean your transmission service is needed. A few of these include: Transmission is having trouble engaging/staying in the proper gear. Your vehicle’s shifting is delayed or skipping gears entirely. You can feel your vehicle slipping as it tries to shift gears. You see leaking transmission fluid. You smell burning. Grinding or humming noises while driving. Your engine is revving excessively high. With any issues like these, it’s important not to wait. Schedule a transmission repair in San Marcos, Tx as soon as possible.