DoctorDiff Sure-Trac is a fully machined, forged steel Dana 60 posi which operates similar to an Eaton True-Trac. It features 12 helical gears (6 per side) and upgraded 35 spline side gears.
Fits all 3.23-4.30 street gears, EXCEPT Richmond.
Use conventional 85 W 140, GL-5 grade gear lube. Friction modifier is not necessary.