Transmission leaks may be caused by lose pan bolts or drain plugs, a cracked transmission pan gasket, a faulty torque convertor, damaged transmission fluid lines or a warped pan gasket, according to CarsDirect. There are various reasons for transmission leaks. Most have easy fixes, while some can be quite expensive.

Transmission leaks often result from lose pan bolts after a filter change. Leaks may also come out of drain plugs if they aren't well secured after changing the transmission fluid. Lose drain plugs and pan bolts can easily be tightened to stop any leaks.

Cracked transmission gaskets can be another cause of leaks. In this case, the transmission gasket should be replaced to seal the leaks. Transmission gaskets are quite inexpensive, and replacing them is easy.

Sometimes, transmission leaks are caused by a damaged torque convertor. Damage to the torque convertor’s needle bearings or a chink in the torque convertor’s body can cause leaks that may be difficult to detect and quite expensive to repair.

Debris on the road may damage or puncture transmission fluid lines and cause leaks. These lines are usually quite durable, but they are not totally immune to damage.

Transmission leaks are damaging to the environment. Transmission fluid is just as harmful as other petroleum-based products, and it can cause significant damage to the environment. For instance, soil contaminated with transmission fluid can be toxic to insects and rodents that keep pests in balance.

Leaked transmission fluid can also find its way to a water source either by seeping through asphalt or being carried by the rain. Water contaminated with leaked transmission fluid can cause irreparable damage to humans and animals.