when the engine was replaced did you replace the Crank sprocket, Accessory drive pully and the Crankshaft bolt? IMO All three of these Items need to be replaced once this happens. Proper torque of the crankshaft bolt is criticle. If the pully slips the locating pin on the crank sprocket shears off, the pully spins on the face of the crank and messes up the mating surfaces. The pully is held tight to the crank sprocket from the clamping force of the bolt if this force is not sufficient the wimpy pin is not enoough to keep the pully from spinning..

99 Gen 2.5, fixing blown head gasket
89 SWB- 33's, ARB Front locker, SR rear locker/axle, SR F brakes, winch, WST Offroad Armor all Around, 2.85 Aussie T-case Gears (SOLD)
Sold: (2) 95 SR's, 86 SWB, 90LWB, 91 LWB
-Can Change a timing belt in my sleep..