Went to change the fluid on my 04 exp 5.4. I dropped the pan and noticed a yellow plastic mushroom piece sitting in the bottom of my pan. I can't figure out where it goes. Everthing else looks clean ship shape. Any help would be greatly appreciated.

 

Not to worry, that plug is in the hole to keep the oil from coming out when Ford assembles the truck, when they mate the motor to the transmission it pushes that plug inside.
If you find that plug in your transmission it is an indication the pan was never dropped since the truck was new.
Just replace the filter , trash the mushroom plug , refill with the same amount of oil you drained.
Done.

 

You are my hero! Thank you.

 

That will get about half the fluid changed. You should look through here for complete flush techniques and do it all. How many miles do you have on it? It should be done every 30k.

 

Mercon V is good for more than 30k, but it does not last forever either. The 04 tranny will not allow you to drain the torque converter via drain plug, but if you want, you can pull the lines (or cut them) and drain that way, with the engine running.

Stupid of Ford and others as well to build trannies with no plan for fluid changes. All the approaches are messy at best.

 

No need to cut anything. Remove the rear line from the trans, attach a clear tube to the line and put the other end into a bucket, start the car and let it run for at least 30 seconds to pump the old fluid out. Attach line, fill the trans through the dipstick with new fluid, start the car and let it flow through the trans, adjust level as needed. This is very easy and it takes longer to set up then to do the job.

 

Is that the best way to get all the old fluid out?
How many quarts can you drain by dropping the pan and disconnect the line as you mentioned above?

 

That gets MOST of the fluid out. From 03 on, there is a thermostatic block in the lines to the radiator that will prevent the fluid that is in the radiator core from being pumped out. Some people choose to mess with that as well, though I did not.

I think total capacity of the system is like 12 quarts (varies with tranny) and you get about 10- 11 out with the pan and lines.

I also installed a drain plug on the pan when I had mine off -- dropping the pan the first time, while its still full of liquid is a mess, but next time, if there ever is a next time, will be a litle easier.

 

Got it thanks.
I dropped my pan, replaced the filter and installed a drain plug back in December.
I will only drain at this time using the method described above , then it should be good for another 30k miles .
Thank you.