I used to run some high miles (40-50k / year) especially with my old 5.9 which I still have. I still do about 20k or so but it’s split between vehicles.

I would drop pan, change filter, and refill oil (atf+4 usually 6-6.5 qts) I have some videos on this process. I don’t think a flush is necessary to do.

@@OutpostCTD Okay, thanks a lot, man.

@@OutpostCTD How many times should I drop the pin to completely clear the transmission system?

@@maliknolan5711 well you’ll be changing about 1/3 of the oil. It doesn’t seem like much But it will make a difference. If your oil looks burnt you can try running 20k mile intervals before doing it again. And over time it will start looking good. This is how my trans was. If your oil looks more red than black you are good and can run 30k miles.

The trans fluid is not black. It's red like wine. I just want to keep on top of this maintenance. Because I know these are the weak points of these trucks.