Took my spool out to put my trutrac in and were the gear mounts is a different thickness causing gears to bind. Shown in pic...

 

What gears are you running and what is the carrier break of the two carriers. The last question I'm going to guess you don't know. Depending on what axle you're running your carrier will change with different gear ratios, like 4.10 and down numerically and 4.30 and up.

 

Stocks. And I think there 3 somethings. I think after looking at the locker more you can take it apart and shim it. Not positive but guess ill see tommorow

 

You may want to check the model number on the locker cause it may not work with your gear ratio.