When you say "I just finished rebuilding the rear axle." and we assume that it operated somewhat before hand, It means, of course, that you really did something major wrong. Why did you do this without knowing anything was wrong? Are you experienced at this? You sound like it and you sound like you have measuring tools. I ask because these answers can help us know what was and what is. You just need to go over the procedure, the proper procedure that is, one more time. You need to read the diagram and be sure it has all the parts, some may have been missing from it before you got it. Something big and obvious. CAN NOT move forward without that check. That's why Jerry wants pics. If you put all the parts back in, it would not do what you say it's doing. Being off by .010 or .020 will not make it slip teeth, just destroy something or growl.What is the 1/4" measurement exactly? . 1/4" from what to what? Is this backlash, tooth engagement depth, slop somewhere??? 1/4" is a big number. Is the spider gear shaft missing in your photobucket pic? (see pic in OP's profile/web page)