Labor Day Pain in the Rear End

[California Charlie]

Hi Guys, Once looking for some answers to me being stumped once again with trying to make progress on my 1931 Model A Ford. Making one step forward and two steps backward.

Here's what's going on. I'm reassembling the rear end differential. Went through the Pre-Load process, etc.

When I install both left and right axle housings to the center housing, and torque the bolts to 35in pounds, the left axle freewheels and appears not attached to the driveshaft.

When I separate the right axle housing from the center housing, leaving the left housing still attached, the left axle then appears firmly connected to the driveshaft gearing. When I spin the driveshaft the left axle then turns.

Then when I re-tighten the right axle housing to the center housing, the left axle once again appears to detach from the driveshaft and freewheels.

I can't figure out what is happening with this assembly process to create the issue I'm having. Any thoughts from anyone.

I have every restoration book under the sun, but can't seem to find this situation in any of them.

Thanks very much for anyone's input to resolving this matter.