What happens when you put in too much transmission fluid?

I have an automatic transmission and I think it‘s a quart over.

Too Much Transmission Fluid

Overfilling an automatic transmission can raise the fluid level to the point where the internal moving components i.e planetary gear sets, imput and output shafts, etc. are physically immersed in the oil, which churns up the oil causing it to foam, and be pushed out of the case vent, filler tube, etc. Also, when the oil is foamy the pump picks up this mixture of air entranced oil and the transmission pressures to clutches, bands and other components drops causing erratic transmission function and slipping. The solution is to drain off the excess fluid by siphoning from the filler tube, draining off through a removed cooler line or by removing the transmission pan drain plug (if equipped), or removing the transmission pan.

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