Okay I saw this on another board and thought I would provide here.

Machinist's Workshop magazine tested penetrants for break out torque on rusted nuts. They arranged a subjective test of all the popular penetrants with the control being the torque required to remove the nut from a "scientifically rusted" environment. The results are as follows;
Penetrating oil..... Average load
None ..................... 516 pounds
WD-40 .................. 238 pounds
PB Blaster ............. 214 pounds
Liquid Wrench ..... 127 pounds
Kano Kroil ............ 106 pounds
ATF-Acetone mix....53 pounds
The ATF-Acetone mix was a "home brew" mix of 50-50 automatic transmission fluid and acetone.

I have used the home brew recommended by USMCHARLEYJEEPGUY it works well...the only problem is that it has a very short shelf life so only mix enough for what you are going to use immediately.
Truck