Get out the waders it's getting deep in here ...

You need to add MORE than the amount you take off the cones , if the cones are already bottomed out then the spiders already have increased backlash.

All that metal in the oil is not a myth ... the cones are wearing out because they are grinding away EVERY time the car turns ... spiders will weld themselves to the spider pinion when the cones bottom and you keep doing burnouts, it can even happen to a peg leg after 2 many one wheel burnouts.

If one hasn't seen the damage they are either Helen Keller blind or inspecting the parts from across a dimly lit football stadium. ...just look at the gear teeth, and the bearing rollers and races with a magnifying glass to see all the little pits.