I've heard too many horror stories about pressure flushes and reverse flushes from shops for transmissions. Also, just dropping the pan and doing the filter doesn't get to the tq convertor.

So, I read a while back about using the transmission pump to naturally pull and push new fluid in and out of the transmission. My questions is: Can this be performed via the inlet/outlet lines of the aux trans cooler? Basically, fill a bucket up with good trans fluid of your choice and have the other end in a "bad fluid" catcher or oil pan. Start the truck and let the transmission pump naturally pull the good fluid in and push the old fluid out. When it's done, you can then crack the pan and replace the filter knowing that all of the good fluid has pushed the old/bad fluid out and a good filter can then go in its place.

Does that make sense?

 

Anyone ever try to do a "flush" this way?

 

In theory there is nothing wrong with doing it this way, but it does waste a lot of very expensive fluid in the process. Some trans don't cycle fluid through the cooler until they reach operating temp, not sure if that applies to rangers. Also, changing all of the fluid at one time can actually make the fluid TOO slick and cause old clutches/bands to start slipping.

You have a 4x4 so changing just the fluid in the pan is about 4 quarts IIRC, that is good enough.

 

Gottcha....thanks

 

Might as well throw on a drain plug while you're at it.

 

Can the fluid in the pan be sucked out of the dipstick/filler tube?

I have a Pela6000 for doing that with the engine oil.

 

I can't think of any reason why it wouldn't. Changing the filter is just as important though, so you would need to take the pan off anyway.

 

The truck's almost new, only 12,000 km. I want to get some synthetic ATF into it. So the filter should be fine.

Thanks.