Posted on 2/27/2026

Overfilling transmission fluid sounds harmless. A lot of people assume extra fluid just gives you extra protection. In reality, an automatic transmission is picky about fluid level, and too much can cause problems that feel like slipping, harsh shifting, or strange behavior when the transmission is hot. If your car started acting up right after a top-off or service, an overfill is worth considering. Transmission Fluid Level Too High Automatic transmissions are designed for the fluid to sit at a specific height in the pan. The pump draws fluid, sends it through internal passages, and returns it to the pan. When the level is too high, rotating parts can whip the fluid into foam. Foamy fluid does not behave like normal fluid. It can compress, trap air, and reduce consistent pressure. That pressure is what applies clutches and bands inside the transmission, so inconsistent pressure can translate into inconsistent shifting ... read more