I have a 69 B body 8 3/4 489 case with 3:23 OPEN gears. While doing a brake job I decided to change the inner grease seals. The outer seals wept a little grease but not much. Before I removed the axles I did not notice any endplay on either axle. I replaced the inner seal, cleaned and re greased the bearings and installed new white foam dust seals. While cleaning I did not turn the right side adjuster since I thought it would be close in the ballpark where it should be after re installing the axles.
Well both axles had a ton of in/out play. I had to turn the right adjuster over a full turn counter clockwise to get the play out of the right side. I have it at .013 but the left side axle still has a ton of in/out play. Shouldn't the play on both sides snug up when setting the preload or did I do something wrong ? Or do I have a bad bearing ? The bearings looked good and nothing was changed except for cleaning and greasing. ( the left bearing did not have much of any grease when I cleaned it )

If I'm remember correctly the adjuster should be on the passenger side, they say to install the driver side axle first and tighten up all five nuts so they are tight, then install the passenger side and set the end p[ay on it to be from.0005 to no more than .006. I think. I shoot for .0005 to .0030 end play max with stock axles bearings, zero with green axle ball bearings
Tapered Timken axle and wheel bearing are designed to be use with preload on them so minimum end play will work fine

Are you sure it's an open diff and not just a worn out Sure Grip?

Open should have a one piece thrust block, Sure Grip have thrust buttons on the block which are known to fall out when axles are pulled.

Either way, endplay should be the same on both sides. If the axles are butted against the thrust block, they essentially act like a single shaft all the way through.

thanks for the info and ideas but this thing was bugging me and I thought about it all night. Guess what ? it was my mistake, I was turning the adjuster the wrong direction. It is supposed to go clockwise to put pressure on the right bearing and also push the right axle shaft to put pressure on the left axle shaft and snug up that bearing also. I was adjusting it backward turning the adjuster counter clockwise because that is what I read on another Mopar board where they told how to do the bearing preload. I just had to think it through . I was having a brain f art and getting frustrated with the whole preload procedure. It is good now but I probably ruined an outer seal by turning the adjuster the wrong way.

glad it was something simple.
i could start listing things i did over my lifetime by "exhaling gas through my brain", but it would take so much time i would wear out three keyboards typing them out !
don't feel bad. it's part of the " life learning experience"..........

We all have those moments.

The good news is that grease is pretty easy to contain. You might not need to go after the seal. Considering how much of a PITA and expense that is, I'd take the gamble.

That makes me feel so much better. We all have Senior Moments for sure. 👌

Hey now, I don't qualify as senior yet.

You probably do, to a teenager

teenagers look at me as weird..........