Purchased 2007 Xterra S 4X4 AT 98,000 miles. CoParts special, salvage title, no rust, no codes (after some ABS Sensors and IPDM replacement), now it runs great, $1700 (4X4's are expensive in NW). Have replaced all fluids, Engine Oil, Front & Rear Differentials, Brake, ATF, Transfer, Antifreeze. Did transmission/radiator bypass. Have put about 500 miles on and off road with no problems. Is there any way to tell if the Radiator has been previously replaced? I really do not like the design of precooling the ATF with the Radiator, but there is no way to check the ATF temp at this point. Purchased Xterra for mainly off roading and need a fair amount of reliability. Thoughts on ATF cooling, Radiator replacement, Secondary ATF Cooler, Electric Fan, ATF Temperature Sensor placement... ???