Hey guys, I had a neighbor who was a mechanic tell me that I could change the transmission fluid in my 2005 Ford E-250 by popping the trans fluid cooler line off and turning the car on, then just letting it pump out. I am a bit scared to do this, but he said as long as you are not moving there shouldn't be issues and it will be much cleaner than dropping the pan. I would love to hear if you guys think this is safe to do without blowing up my transmission. It was a few months ago at this point, so I don't remember the details but i think he said to just shift through gears while not moving and it will pump out not all of it, but a good amount.

 

There is a reason the lines go to a cooler, to keep the fluid temp down and take heat away from the trans moving components.

Anytime the engine is running the trans pump assy is moving that fluid . As you know a transmission's worst enemy is HEAT.

You will not know when the pump is getting too hot until it is too late.Don't know if you want to risk that.
There are advantages to dropping the trans pan, among which are you can change a possibly "due for change" filter , remove all the sediment sitting in the bottom of the pan and knowing you did the job right.

It is not a complicated procedure on most trans, and if you don't have the correct info and tools best left to a shop that does. Cleanliness is essential, if one piece of grit gets into the valves of the valve body , it can do serious damage and now requires other work and expense.

Yes if you use the open line change procedure you might not have that problem, but could invite other problems.