Hello All,
I have FLUSHED every transmission I've owned. After the Pan drop and Filter change, I would simply disconnect the Transmission Fluid Line returning from the Radiator or Aux Cooler. Then with the vehicle running and someone in the vehicle shifting through the Gears; the old Fluid got pumped out as I was pumping new Fluid in. My 2021, F-150, 3.5 with the 10R80 does not have any Transmission Fluid Lines leaving the Transmission. The dealers advertise that they perform this Service. How does one Flush the 10R80?

 

I'm not aware of any way to hook an actual flush machine to a 10R80. When I do a trans service, I'll drop the pan, remove the filter, and then loosen the valve body a little. By loosening the valve body, it allows the fluid from the converter and further up in the gear train to drain. I end up getting between 9 and 10 quarts drained when doing it this way, which is about 75% of it.

 

Thanks for the tip about loosening the valve body. Since my original post, I've done more research and concluded what you have stated. As a prior F/A-18 Hydraulics & Structures Mechanic, and lifelong gearhead; I know it can be done. If someone would fabricate a dual "T" fitting that would go between the Trans Fluid Cooler/Warmer component- problem solve. Of course it would be a tight fit in the tunnel and longer Cooler/Warmer mount bolts would be needed, but a company beyond my capabilities could make it happen..... B&M are you out there? Now I really want to know what the dealerships do during their advertised Transmission "flush" service.

 

What about by temporarily removing the thermal valves inside the valve body and at the transmission fluid radiator up front? Or I guess if you're already removing the valve body, you'd just have to temporarily remove the valve at the transmission radiator. That should open the whole circuit for flush by-pass, no?

 

If you do as stated and get 75%, with regular maintenance schedules it should go 200k unless the CDF drum failure occurs of which no amount of maintenance can prevent.

 

I think that's the right move for my transmission. Fluid is pretty dark so I don't want to go dislodging anything that's keeping it in good order. That said, I'm hoping this P0741 code is literally just a TCC valve issue and not related to the bigger CDF drum problems

 

If you still have the stock pan on yours, get a extractor so you can suck the fluid out of the fill/check port of the passengers side of the trans. You should be able to suck out ~8L through the fill port. When you drop the pan (stock pan I am referring to), there will be about a quart left in the pan and then when you drop the filter, there is almost .5 in there, so be ready for some mess possibly. We let it sit there and drain/drip for another 30 minutes, then put the pan back on and began the fill process. I added a PPE pan so I would have a drain plug the next time.

Pan gasket is a re-use item, if in good condition obviously. Torque values for the pan is in inch pounds! Checking the level once up to temp is a bit of a bear as the check port is directly next to passenger side cat! I use a pair of grill gloves when I do it, that cat will get ya!

 

How often y'all servicing the 10 speed? How often does Ford recommend?

 

Ford has the service date at 120 or 150,000 miles...I can't recall the exact number.

 

I’m at 2yr 50,000km, will drop the pan once I got some nicer weather.