i have heard that if u weld on a rear that u need to empty it out. this is what th eold timers havetold me. not to heat up the gear oil. i have built a custom 4 link on my street truck but need to weld it to the rear. what is the truth? olso i like to arc weld on my trucks for good firm welds what rods do you suggest? 6013, 6011 please excuse the typos i broke my finger at work it is a little hard to type with one hand.