There is no rough way to do this kind of work. Rear end clearances must be a balance between pinion offset and ring gear offset. There are precision specs for both measurements. Requires runout gauges,crush sleeves, thrust washers, etc to measure and set backlash and proper position of these two components. You've already figured out you have excessive backlash and it's only going to get worse. Get the rear end checked pronto before you end up with a really expensive repair job.
[This message has been edited by jeffsr (edited 01-21-2000).]