5 Causes of Automatic Transmission Fluid Leaks (and Repair Cost)

Your automatic transmission has lots of moving components and parts inside of it. Like with the parts of the engine, the transmission’s moving parts will also generate a lot of heat as they rub together. This means that the parts of the transmission will need to be lubricated in a similar way that the engine needs to be lubricated. The only difference is the transmission will use transmission fluid as its lubricant instead of oil. If you have an adequate amount of transmission fluid in your transmission, then it will be able to cool these internal parts and even assist in delivering power to the transmission from the engine.

Leaking Transmission Fluid Causes

You can normally wait until you drive 100,000 miles before you need to change your automatic transmission fluid. However, you could still lose this fluid if a leak were to occur somewhere in the transmission system. You will notice when these leaks are happening because there will be red fluid on the ground or road underneath your car. This redness is the color of the transmission fluid. If you see this under your car, then you need to repair the leak immediately. You will also have to put new transmission fluid in your vehicle.

To help you spot where the leak is coming from, here are the top 5 causes of automatic transmission fluid leaks. This should give you some good ideas.

Bad Transmission Pan Gasket – Every automatic transmission vehicle has a transmission pan gasket which stores the transmission fluid. The mechanical seal which rests in between the pan and the transmission is called the transmission pan gasket. This component is what prevents transmission fluid from spilling out as it is transferred into the transmission from the pan. So, if the gasket were to get damaged or cracked, then it will cause the fluid to leak.

Cracked Torque Pump – The torque pump is what circulates the transmission fluid throughout the entire transmission system. If the pump were to get damaged, then it would either cause the fluid to stop circulating or it would cause the fluid to leak from there. Either way, you will definitely have a big problem on your hands that needs to get fixed fast.

Broken Fluid Line – The transmission’s fluid line is made to be durable because it is constructed from aluminum or steel material. However, if it were to get damaged because of excessive heat exposure or cluttered with debris, the line will eventually crack and then it will leak transmission fluid. Even the tough aluminum or steel material won’t be strong enough to prevent this.

Worn Transmission Pan – The transmission fluid pan will eventually get worn out. Since the pan contains lots of little bolts and drain plugs, a leak can easily occur if any one of these parts were to become loose or damaged. In fact, the pan itself could get damaged if you continue to drive on rough or uneven roads. These types of roads have lots of debris and rocks that will damage the pan significantly and cause leaks to form. If you only have loose plugs or bolts, then you can likely remedy the situation by simply tightening them. But if you lose these parts, then you will need to replace them. Either way, you will need to replace your fluid too.

Cracked Transmission Seals – The transmission seals of an automatic transmission keep the hydraulic pressure in-line. The only problem is these seals are constantly exposed to heat as the transmission is in operation. The seals will eventually get to the point where they will get worn out and crack from all this long-term heat exposure. The seals will then leak transmission fluid. Any of the seals could be leaking this fluid, including the shifter housing seal, plug seal, tail housing seal, output shaft seal, and so on.

Read also: 4 Symptoms of a Bad Flywheel and Replacement Cost

Transmission Leak Repair Cost

If you have an automatic transmission that is leaking fluid, the cost to repair the leak will depend on where the leak is coming from. On average you can expect to pay anywhere from $140 to $210 for the repair job. However, if the front seal is causing the leak, it will increase your expenses because the mechanic must take out the transmission first to get to it. Added taxes and fees will be included too.

5 thoughts on “5 Causes of Automatic Transmission Fluid Leaks (and Repair Cost)”

  1. I have a 1994 Olds Cutlass Supreme S 3.1 and the leak is from the right rear passager side.that leak just started. i did had work done a few weeks ago with a power steering leak and other work done for inspection. I had a slight accident 4 days ago hit my LEFT side.Could that have knocked something loose on the RIGHT side causing it to leak transmission fluid?

  2. I had a gasket repair for a transmission leak by Toyota Is a transmission flush necessary after the repair?

    • I’d defer to someone who’s seen the car in person to know for sure. If you have enough transmission fluid, you’re probably good to go.

  3. i have a 700r4 tranny after the engine has warmed up and turned off the I Lose about 1 quart or more of fluid can this be a problem with the cooling’s line connected wrong or what? I have a small leak in the pan gasket., but its as if someone turned the faucet on. what else could cause this problem? thank Phil 11 25 2020


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