Differential Output Shaft wear

[MetBlue]

I noticed recently there is radial movement, maybe about 1 mm, on the N/S output shaft of my diff.
Runs quietly and no sign of oil seeping out ( which surprises me unless it's already dry !!!).
Looking in service manual, makes me think the shims behind the bearing outer are no longer enough - no doubt through internal wear. It has done over 150k.

Thoughts anyone on route cause. Can't feel anything in O/S shaft, which again surprises me as the cluster is supported by a couple of taper rollers.

Are shims etc all readily available ?

I have my eyes on a used diff up north for OK money. Tempted to swop over then do a rebuild on my diff, which from service manual doesn't look too challenging.

Tony