I am currently changing the u-joints on my truck,, and they are rusted in there,, can't seem to get them to budge. My can of WD is no where to be found so instead i tried a little of the wifes cooking spray. srayed it on and let it sit for bout 5 min. worked

 

my dad uses a 50/50 mixture of diesel fuel and atf. he has even dumped it down the cylinders of an old tractor that was rusted tight and it loosened the pistons up within a couple of days. smoked real bad until the mix was burned out of the cylinders.