Mixing Standard And Synthetic Atf

[mattd]

need to change my trans filter and fluid. was gonna just remove the 6ish qts. that come out with dropping the pan. then repeat a few times untill all fluid is new syn. i have never changed the atf before, but i'm sure its not syn. so for the first few changes i will be mixing reg. and syn. is that ok??

[dsmazz]

Drop the pan, pull the filter, clean the pan, install the new filter, install new gasket, replace pan. Then I always disconnect the ATF line carrying fluid from the tranny to the cooler out front, attach a clear hose, and setup a large bucket or pan. Add about 5 quarts new fluid, have someone in the truck (or car) start the engine while you add fluid to the tranny. When the color changes from the old fluid to the new fluid, signal to stop the engine, reconnect the ATF line to the cooler, top off, check for leaks, drive around for about fifteen minutes, recheck level and top off again. That's how I've always done fluid/filter changes. And the mixture of the two fluids (standard and synthetic) is minimized. Otherwise, if you just add, drop, replace, add more, you'll never get all the old stuff out, and the torque converter won't fully empty of the old fluid. Attached file goes into more detail.

ATF_and_Filter_Change_Procedures.pdf

ATF_and_Filter_Change_Procedures.pdf

ATF_and_Filter_Change_Procedures.pdf

ATF_and_Filter_Change_Procedures.pdf

[markw8]

mattd.

 

There isn't any reason you can't mix the two. If the old fluid is real bad, then make the effort to get all you can out. Mark.

[GatorFan]

Drop the pan, pull the filter, clean the pan, install the new filter, install new gasket, replace pan. Then I always disconnect the ATF line carrying fluid from the tranny to the cooler out front, attach a clear hose, and setup a large bucket or pan. Add about 5 quarts new fluid, have someone in the truck (or car) start the engine while you add fluid to the tranny. When the color changes from the old fluid to the new fluid, signal to stop the engine, reconnect the ATF line to the cooler, top off, check for leaks, drive around for about fifteen minutes, recheck level and top off again. That's how I've always done fluid/filter changes. And the mixture of the two fluids (standard and synthetic) is minimized. Otherwise, if you just add, drop, replace, add more, you'll never get all the old stuff out, and the torque converter won't fully empty of the old fluid. Attached file goes into more detail.

Hey Mazz, great info. I just took mine to a Jiffy Lube, gave them the fluid I wanted it changed to and had them use their machine to flush the system. It was a little more expensive to have them do it but at the time, I lived on a military base. They wouldn't allow you to do any maintenance on your vehicle in base housing which sucked but rules are rules. I watched the Jiffy Lube guys the whole time to make sure they put in my stuff and the whole process took about 20 minutes.

[Texsrt4]

modern synthetic fluids mix just fine with conventional fluids...and it might even be factory synthetic fluid in your trans. if the fluid is in real bad shape, do the best to get it all out. if its still ok then just drain and fill