Transmission fluid is colored green or red so it can be distinguished from other fluids in the vehicle. While it may not be especially dangerous to drive a vehicle that is leaking transmission fluid, it is not a good idea because the vehicle may not run properly. When considering the safety of driving with a transmission fluid leak
What should do if you have a transmission fluid leak?
The first thing you should do is check the transmission fluid level by pulling out the dip stick, (check the owner's manual for the proper procedure, not every vehicle has the same procedure) If the fluid level is below the recommended levels, it's best to have the vehicle towed, driving the vehicle with low transmission fluid could cause damage to the internal parts to the transmission.
What causes transmission fluid leaks?
1) The most common cause of a transmission fluid leak is a seal, it could be an axle seal, output shaft seal, input shaft seal, etc... Other causes of a transmission fluid leak are: transmission fluid lines, hoses, and coolers, it's rare you will ever have a cracked case or a gasket leaking, but it can happen.
2) A car leaking transmission fluid can be caused by a leak in the pan. This can happen through wear and tear over time. The pan can be punctured or the plugs may not be tightened properly. Either way, if you notice transmission fluid, contact a mechanic so they can inspect and repair the fluid leak.
3) A leak in the fluid lines can also be damaged by debris in the road. Furthermore, heat can cause cracks in the lines creating a leak as well. This drains the transmission fluid pretty fast, so it is best to go directly to the mechanic's shop if this happens.
4) Loose or broken seals can cause a leak in the transmission as well. There are various seals throughout the transmission, so it takes time to find the correct leaking seal. A mechanic has the right equipment to diagnose the problem in a timely manner.