Thanks John - I'll do that and see how it works out. I called and checked all over the island for positrack compatible differential lube or the additive - no luck. I'll have to order some in. Life in the tropics...
Patrick - thanks. I read that page before and it's step 4 that had me worried:
"Mark nut and pinion shaft so that in refitting, nut may be returned to its original position on shaft."
The seller loosened and re-tightened the pinion nut with no markings for reference, so I was concerned that I would have to do a full rebuild as a result.