I will be changing the transmission fluid in my truck (03 4WD 4R70W) and am wondering how I can drain the torque converter, since I do not have the drain plug?

I have a copy of Mark Kovalsky's trans. service instructions, but they make no mention of whether the torque converter will be drained as well.

 

Yes, my procedure will change the fluid in the torque converter. It's the easy way to change it since your truck doesn't have a drain plug in the torque converter. The only other way to get the fluid out of the torque converter is to take the trans out, remove the torque converter, and drain it that way.

 

thanks, Mark. also, there are two lines on the side of the transmission, an upper and a lower. how can i tell which is the return line?

 

Start it up. Put your hand on the lines at the radiator and the first one that gets warm is the inlet to the cooler.

 

Unless you take it to a shop that has a fluid exchange machine.

 

Where do you find a copy of Mark Kovalsky's trans service instructions?

 

You can find the most up to date version here:http://www.thedieselstop.com/forums/...1/#post1564217

This version does not address the 4R70 family. The only difference is the total capacity is a bit less (consult your owner's manual, I don't have it) and the cooler lines on the trans are top and bottom, not front and rear. I also don't remember which one is out and which is in. Drive the truck and the hotter one is to the cooler. Remove the cooler of the two.

 

Do you have an aux trans cooler? If so, follow the line that comes FROM the rad to the aux cooler. It should be the bottom line on the rad. That means the upper line to the rad is the trans OUTPUT line.

I'd think in general, even if you don't have an aux cooler, the top line on the rad is going to be the trans OUTPUT line, right?

Well, that's the one I tapped into for my trans temp gauge!

Good luck with it all!

Mitch