Transmission Fluid Fill Level

Today I'm in the middle of changing the transmission fluid on my 2014 4Runner (80K miles) and I noticed something very surprising to me. When I was ready to drain the fluid, I decided to open the Check plug first just to see if anything came out, and if so, how much. At first I thought I had opened the wrong bolt, because 1.5 quarts of fluid came streaming out. But no. This was the correct bolt (5 mm hex).

The transmission was not cold, but I would say only moderately warm as I had just used it for a quick trip to Home Depot about 3 miles away. Maybe it was much hotter than I thought, but I can't believe that the fluid expands that much, such that when very hot, 1.5 quarts would come out. Has anyone noticed this before?

I then drained the rest of the fluid through the drain bolt, and the total fluid I captured was as expected - just under 4 quarts.

This is the first AT fluid change I have done, and I am the original owner and have done all my own maintenance since 30K miles. So the AT fluid that I drained was what was put in at the factory.

I know the fluid expands with temperature, but this seems way more than expected.

 

Possible depending on how hot it was. I'm still guessing after a 3 mile trip it can get warm.

Stolen from bobistheoilguy

Which is I would say its pretty important to follow to procedures if doing it warm. If doing it cold I still think matching what was drained is fine.

 

If you pulled the check plug out Without the engine idling, then you will get a lot more transmission fluid from the check plug.

 

This too.

 

Oh, that's right! Very good point! The engine was OFF when draining, so much more fluid would settle to the bottom and come out of the check hole. With the engine running (which it must be when checking/setting the level), then a fair amount of fluid would be circulating in the transmission. Makes perfect sense. Thanks.

 

Just make sure to fill the last 2 quarts and check the level WITH the engine running. Use a laser thermometer, check fluid level when tranny pan is between 100ºF and 110ºF. I find shorting the ODB pin much too cumbersome.