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An essential part of automotive maintenance is to change your transmission fluid at regular intervals, about every 100,000 miles or so. However, you should still keep an eye on the fluid level to ensure there isn’t a leak somewhere in the system. Of course, that’s not the only way to tell if your transmission is leaking. Here, we discuss how to know if you have a fluid leak, the possible causes of it, and how much it could cost you if it’s left unchecked.

How to know if you have a transmission fluid leak

You could tell if something’s wrong with your transmission if it starts acting strangely, like clunking sounds when it shifts. However, you don’t want to let things get quite that far. The best way to know if it’s leaking fluid is to look underneath your car for fluid spots on the garage floor. Since condensation from the air conditioner evaporator and engine oil can also show up on the pavement below your vehicle, it’s important to pay attention to where the fluid is found and what color it is. 

If a transmission is leaking, you will see a puddle or spot forming on the floor in the middle of the vehicle, according to Access Auto Insurance. The color of the fluid should be red or brownish in color. If you see that, you should get the car to a mechanic as soon as possible so they can determine why it’s leaking. 

Letting it go untouched would be pretty bad because the transmission needs that fluid to keep the gears moving smoothly. If it all leaks out, parts inside of it will get damaged easily, leaving you with either a transmission rebuild or replacement bill, which will be cheap. 

What could cause a transmission fluid leak

Rows of AutoZone transmission fluid on display in a store in Princeton, Illinois
AutoZone transmission fluid | Daniel Acker/Bloomberg via Getty Images

According to Access Auto Insurance, there are four main reasons a transmission might leak fluid. Those include:

1. Debris on the road. Some debris could get kicked up from the tires and sent flying into your transmission pan, causing cracks or punctures, which would allow fluid to leak out, according to Accurate Auto Service Repair

2. Cracked gasket in the pan. This can happen for two reasons. One is that natural wear and tear over time will cause it to crack and allow fluid to pass through it and leak out. The other is when it’s replaced and wasn’t installed properly.

3. Problems with the torque converter. The torque pump sends transmission fluid through the gears. Over time it can wear out, causing it to crack and leak fluid. Also, needle bearings within the converter can get damaged, which will cause fluid to leak as well.

4. Improper transmission fluid change. Sometimes, when you get your transmission fluid replaced, the mechanic won’t reinstall the pan properly. If that’s the case, fluid will leak out onto the ground. 

How costly is it if you don’t deal with the fluid leak?


Can Changing Your Car’s Transmission Fluid Damage it?

As we stated before, not dealing with a fluid leak will damage your transmission. It will either have to be repaired or replaced. Both are pretty costly repairs. So, how much money are we looking at? It’s difficult to pin down an exact price because every mechanic shop will price their services differently, but let’s look at some general costs of both types of jobs.

If your mechanic recommends a repair service, you could be looking at anywhere from $300 to $1,400 for parts, depending on the transmission’s damage. Labor isn’t cheap, either. It could add around $500 to $1,200 for approximately 4-10 hours of work. How much depends on what all is needed for the repair. Of course, if you’re mechanically handy, you might be able to save on labor and do it yourself. 

To replace the transmission, costs can be much higher. You could be paying $1,800 to $3,500 for a brand-new unit, according to Transmission Repair Cost Guide. If you decide to go the used transmission route, it can still be around $800 to $1,500. A rebuilt or remanufactured unit price ranges from $1,100 to $3,400. Then add labor to install it, which could put the bill almost at $5,000.

Periodically check to ensure your transmission isn’t leaking, especially after a routine fluid change. If you stay on top of it and keep clean fluid running through your transmission, you can avoid some pretty costly repair bills in the future.