found the problem in my 7 1/4
these are the pins that hold the spider gears in the s/g diff. my car has four spider gears that link the two axles to each other and to the power. By welding the two together it puts the strain on all four rather than two if they are worn a bit more and makes the centers alot stronger because they are so thin. Does that make sense? just asking cuz it does to me but then i did all the work :D