I assume its outa the vehicle ????
Old circle tracker trick is bolt a couple wheels that your sure are straight on it.
set those wheels on milk crates, stretch a tape measure across both wheels (much like setting toe in) then have a buddy spin the housing slowly while you watch the tape for runout, You can usually straighten a slightly bent tube by finding the high spot on the axle tube,heat about a half dollar size spot(red hot) on the high spot and quench with a wet rag, then recheck your measurements again, If ya really want to be amazed have your buddy hold the tape across those wheels while ya heat and quench, you'll be very surprized how much it moves..........