Ok...I know this is over 1 year old...but per your pm's to me yesterday it seems you still have the issue even after taking the TT out and flipping the gears?

Here's the related part numbers for the TT and other lockers...
Positractions & Lockers
Differential---------- ARB Air Locker-- Detroit Locker--- Lockright TRD--------------- Truetrac
8” Toyota Rear--------- ARBRD01---- DET187S-61A---- PT 1610 TRDRN001--------- TT 913A348
8” Toyota Front-------- ARBRD01---- DET187S-61A---- PT 1610 TRDRN001--------- TT 913A318
8” Toyota V6 & Turbo-- ARBRD23 ----DET187S-61B----- PT 1620 TRDVN001 ----------TT 913A321

So while you were inside the TT you found a front part number stamped in it ?

The helical teeth looked just fine?

When are you putting the Aussie in?