What is a common symptom indicating a failing transmission seal?

A common symptom indicating a failing transmission seal is fluid leakage. Transmission seals are designed to keep the transmission fluid contained within the transmission casing. When these seals wear out or become damaged, fluid can escape, leading to visible leaks underneath the vehicle. This not only reduces the fluid level in the transmission but can also affect the transmission's ability to operate efficiently. Lack of proper lubrication can lead to increased friction and potential damage to the transmission components, causing further operational issues.

While noise, a burning smell, and poor acceleration can be signs of other transmission problems, they are not directly indicative of a failing seal. Noise may come from various sources within the transmission, a burning smell often indicates overheating, and poor acceleration can stem from multiple mechanical or electronic issues affecting the vehicle's performance. Thus, fluid leakage stands out as a clear and direct signal of a transmission seal failure.