Symptoms
- Puddle or spots under the middle of the car
- Reddish, pink, or brown fluid (not the yellow-green of coolant or black of oil)
- Low fluid level on the dipstick
- Slipping or delayed shifting from fluid loss
Likely causes
- CommonWorn pan gasketThe gasket sealing the transmission pan hardens and shrinks over time, allowing seepage.
- CommonWorn axle or input shaft sealSeals where shafts exit the transmission wear and leak, often dripping from a specific spot.
- PossibleLoose or damaged cooler line fittingLines carrying fluid to the transmission cooler can loosen or crack, especially after other work.
- PossibleCracked transmission panRoad debris or a hard impact can crack the pan itself.
- Less commonFailed torque converter sealA seal deeper in the transmission can leak and is more involved to access.
What to do
- Place cardboard under the car overnight to catch drips and see roughly where the leak originates front-to-back.
- Check the fluid color: red/pink/brown and slightly oily points to transmission fluid rather than coolant or engine oil.
- Check the fluid level on the dipstick (if equipped) and top off temporarily if it's noticeably low.
- Look at the pan edges, visible seals, and cooler line fittings for wetness or drips.
- Avoid driving further than necessary if the level keeps dropping, since low fluid causes slipping and heat damage.
- Have a mechanic pressure-test or visually confirm the exact leak source if it's not obvious.
- Get the specific gasket, seal, or line repaired rather than just topping off fluid repeatedly.
Tools and parts
- Cardboard or leak mat
- Dipstick
- Flashlight
Transmission pan gasket or sealSearch: “transmission pan gasket [make model year]”
When to call a pro
See a mechanic to pinpoint and repair the leak if it's not an easy DIY pan gasket job, especially if the level keeps dropping between checks.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.