From Tekno RC:
Ryan Lutz demonstrating how we recommend building Tekno RC differentials. This results in leak free, smooth and consistent differential. Below are the part numbers for the Tekno RC tools used:
TKR5447B – Complete Center Differential (46t, NB48.3/NT48.3)
TKR1105 – XT Hex Wrench (2.0mm, adjustable length, 4mm shank)