DIY: Full Flush for Automatic Transmission

at the overflow plug, you let the NEW fluid drip out B4 u tighten correct? Then do the "Temp check" and go under the truck, loosen the overflow plug and wait to see fluid coming out of the plug.

 

NO you fill it then get it into temp check mode and remove the plug, when it starts to “dribble” install plug


You must fill it with exactly what you removed plus some

 

okay, close the overflow plug, then fill it with NEW fluid, do a temp check mode, then remove the plug all the way and let the fluid dribble a little then tighten back the plug...correct?

 

You remove the overflow plug as soon as it’s in temp check mode...leave the truck running

 

Overflow plug, right?

 

Yes whoops lol

 

I decided not do to a full flush....so I drained about 2 1/2 qts...refill 3 qts back in then I remove the overflow plug and about 1 qt of the new fluid came out...is that normal?

 

Just did mine today, I had about 2 qts come out, added 2.5ish and let it drip when at temp. From what I read usually 2.5-3.5 qts comes out?

 

Depends, was the ATF temp between 115-130? ATF expands as it warms up; thus if you open the overflow plug when too cold, you will end up with too much ATF in the tranny; remove the plug when the ATF is too hot and you'll be removing too much ATF.

 

I opened the overflow plug when it was cold.

 

Then you may be overfilled. How much depends on how cold it was. An IR gun aimed at the trany pan will be good enough to get the temperature. Go for 120 degrees. And remember that the truck must be leveled when you do the draining. Put a magnetic level underneath the chasis. Use a floor jack at the front or rear to level it.

 

thanks for the tips! I will check and jack the truck up to level if needed.

 

sprayer pumps

what did u use to pump the new fluid in?

 

A pump like this one

$12 Performance Tool W1156 Grip Clip Transfer Pump/ Siphon Fluid Transfer Pump Kit for Water, Oil, Liquid, and Air, Black/Clear, 48" Hoses

https://www.amazon.com/dp/B00J8331U6
I have a couple of them in different brands, the last one I bought was a penzoil branded one from Walmart. It works fine, they are all about the same in my experience.

 

Do you have to drain the pan and refill what you drained first? Or can you do the whole thing start to finish (minus the level check/add) from the AT cooler lines?

 

You dont have to drain the pan. I dropped the pan and replaced the filter while I was at it. Did it at 138k miles.

 

I did as well and would recommend dropping the pan

 

I think it's best to drain the pan first, but I have done it entirely through the cooler lines on other vehicles before. You just don't get as much old fluid out it you don't drain the pan first.

 

I ran the vehicle and pumped new fluid until nothing but clean fluid ran out of the line.

 

just finish doing a full flush, wasn't too bad. Thanks everyone for the help!