What would happen if I accidentally filled my automatic transmission with engine oil instead of transmission fluid?

Answer 1

It doesn't matter, because anyone that careless couldn't fill the transmission fluid.

Answer 2

If you caught the mistake fairly soon and did the proper drain, change filter, refill with proper fluid, run for a day and then repeat the process (to clean out any residual oil), there should be zero damage to the transmission. ATF fluid is essentially motor oil with additives, so a short exposure won't do any harm. Longer term, the oil will not function as ATF fluid is designed to and damage to the transmission is likely.

Answer 3

Try it. Report back on the results.

Answer 4

Transmission would slip and car won't go. So you don't do that.

Answer 5

Year make and model.  There will be transmission shifting problems and your transmission will have a short life.

Answer 6

AC Transit, in Oakland, California, experimented with that in their diesel buses many years ago. It worked and the transmissions held up fine. Automobile transmissions would be affected according to how the transmission clutches and seals tolerated motor oil- or not.

Answer 7

You'll ruin the tranny if you don't drain all the motor oil out. I'd go as far as running the motor and shifting through the gears and then draining and filling the transmission again to try and make sure all the motor oil is out.

Answer 8

I've never done it, nor do I personally know anyone who has, but I suspect it would be incompatible & tour tranny would fail (catastrophically) relatively quickly. 

Answer 9

Ruin your auto trans in short order.

Answer 10

You would spend a lot of time walking.