I'm planning on doing a tranny fluid exchange this weekend and I've been reading lots of posts on here. The easiest way seems to be tapping into the transmission fluid cooler lines and letting the pump do the work.

One often-referred to write-up, by Mark Kovalsky, seems thorough and I plan to follow that. It reads "4. Disconnect the transmission fluid return line at the transmission - from where the ATF returns to the transmission cooler. This is the line toward the rear of the transmission." Unfortunately, there's no way I can get a wrench on the spot where the lines run into the tranny, and even if I could, they're situated one on top of the other, vs front and rear.

I'm hoping someone on here can tell me that I can use the spot before the tranny, where the two lines run into a square "junction box." It looks like the lines are threaded on there and could be disconnected easily. Or, possibly I could disconnect at the tranny cooler, as long as the lines disconnect with a decoupler tool similar to the one used on the fuel filter, as I have a selection of those.

Any other easily accessed spots that someone can suggest would be welcomed as well. TIA.

 

Forgot to mention, its a 2004 (new body style) w/ AT.

 

Edit - I'm still planning on proceeding with the ATF exchange this weekend, I guess I'll see which line I can tap into.

Another question - I have the tow pkg with the auxiliary tranny cooler. I know the ATF capacity for the 4R70W is 14 qts, will I need more than that with the extra cooler and lines?

 

On the 2004 4.6 I had with no trailer tow, I used the cooler lines just in front of the radiator. I used 18 qts to make sure all of the crud came out. 14 Qts is an exact change not allowing for any residual fluid the chance to come out. YMMV

 

You should probably drop the pan, wipe it out, and replace the filter. Anything holding you back?

 

Filter does not need to be replaced.

 

I actually dropped the pan and replaced the filter 5-6 years and 50k miles ago, but since that only exchanges ~4.5 qts of fluid, I wanted to do a more complete job this time.

I followed the write-up on here, and despite my concerns I was able to disconnect the ATF return line where it meets the transmission housing. I did end up taking the line loose (not off) where it runs into the "junction box", just to give the line some slack.

The whole job, including dropping the pan again to clean it out, took me about 2.5 hours, including clean-up. I used 15 qts of fluid total. And yes, I did replace the filter again since I already had it out and it only cost 13 bucks.