I'm midway through a rear-end swap. This axle has had a lot of slop in the gears and I acquired a good 1968 replacement from Mario_E. The replacement has been cleaned and painted and it is now ready for installation.

before and after dropping the original rear, I checked the U-joints and found no play whatsoever. I checked by grabbing either end of the driveshaft and applying twist force to each U-joint. No movement or hint of movement, so I think I'm going to rule them out for the moment.

What I have found so far is that the passenger side drum was very difficult to remove. The brake shoes were moving with the drum and I found that the rear shoe retaining spring had come off. There may have been some shoe edge wear, but the light was fading pretty quick and I had to come in. I'll check again in the morning.

This might be the problem or not. Once I've buttoned up the new rear axle and had a proper test drive I'll know more. At least I'll have reduced the rear end gear slop...