MB241229 is the shim set (for 1 hub) with several assorted washer shims.

To determine what (if anything) you need:

Make sure the t-case is not in 4WD and the hubs are not locked. With the clip installed on the axle, reach behind the hub and grab the axle joint - rotate it forward and back until you can judge the limits of free play and set it at the mid-point between forward and back resistance. The mid-point is where you have maximum axial end play. From this position, push/pull the axle in and out. Standard spec range is 0.008 - 0.020". Use the shim from the assortment that puts end play in spec.

Good luck,
Frank