is this caused by diff pull?

[blueb8llz]

my 3905 emaxx drives straight as an arrow when it moves forward and back. but, as soon as i get some power on it...20 mph+ if pulls left. the harder the acceleration, the worse it gets.

i currently have stock diffs with 30k lube in front and rear. seems to me, there is no reason for the diff to unload to one side more than the other. is there something wrong with my diffs? something else?

something else i had noticed is if i had my truck on a stand and turn all the way to the left or right it would go back to exact center, but if i was to turn left or right very minimal, it would just stay to the left or right and not even try to return back to the center. is this whats causing it? how do i fix this even if its not the problem?

is my toe in off on all the wheels or something...or is the turnbuckles different lengths, or camber off? i dont have the gauges to do these things, but from my naked eye...they look to be all the same length or look the same.