what happens if you overfill a transmission?
<answer> It causes the fluid to foam, leading to erratic gear shifting, oil starvation and transmission damage. <context> Overfilling an automatic transmission causes the fluid to foam, leading to erratic gear shifting, oil starvation and transmission damage. Overfilling a manual transmission causes the fluid to leak from the vent and the gear trains to slow down when the clutch is depressed, leading to gear shifting problems.