Q: Can too much transmission fluid cause speedometer malfunctions?

asked by on February 27, 2017

Shortly after I had my entire automatic transmission rebuilt, I received two traffic citations. I later had my oil changed (by a different auto shop), and they found that my transmission was over-filled.

I know enough about cars to know that too much transmission fluid will cause a transmission to "slip". However, I need a Toyota transmission expert to reply to this message, and indicate the "possibility" or "probability" that a speedometer can malfunction when there is too much fluid in the transmission.

My car has 130000 miles.
My car has an automatic transmission.

Hi there. In most cases when you overfill the transmission fluid it can cause excessive foaming of the fluid or possible internal component failure due to excessive pressure inside the hydraulic lines. Sensors like the speed sensors however are rarely impacted by this situation. However, in regards to the possibility of probability of this; I would say perhaps a 10% chance.

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