Will the axle spin freely in both directions off the bike? Could be missing a spacer or a bearing isn't seated. Here is a diagram of the rear hub though you can find a better one on SRAM's website : https://www.veloruf.de/n/shimanoteile.html?id=50191227 .

Where did you purchase the wheelset as it should be under warranty.

 

The spacer between the freehub and the main drive side hub bearing may be too short. Rotating the wheel backwards may cause the drive side end cap to thread on tighter and compress the freehub. If the spacer behind the freehub is either missing or too small then the bearings will lock up when compressed and cause this.

 

Free hub side 12x142 axle end cap does not move freely on or off the bike.

Removed the 12x142 end caps, replaced them with 9x135 end caps which also came with the wheel and the wheel rotates forward and backward freely. Based on this result, the culprit looks to be the 12x142 free hub side end cap?

 

I don't have this particular hub so I cant say for sure what's wrong. If your 9 x 135 end cap (actually it is a 10 x 135 end cap, 9mm is for a front fork) is bottoming out on the axle then it can't push on the freehub and lock it up. These two end caps should be the same and they should both bottom out on the inner race of the outside freehub bearing.

Do those end caps thread on, or press on? When the wheel is rotated backwards it will cause the drive side end cap to thread on tighter, if it is threaded. Something is clearing binding. Possibly the endcap is pressing on the wrong part of the hub or the freehub is being compressed because a spacer is too narrow.

The 12 x 142 end cap might not be the correct one for an XD Driver. Sometimes the Shimano and XD freehubs use different end caps.

You should be able to test this out of the bike while holding the end caps in your hands.

 

Did you ever figure this out? Having the same problem with an eagle cassette and I9 hub with XD body. Totally bizarre

Sent from my SAMSUNG-SM-G925A using Tapatalk

 

Yup, new end caps didn’t resolve the issue. Bought a new hub, issue resolved. It’s still a mystery.