1983 Jeep Wagoneer ad. A new “Selec-Trac” part time 2wd/4wd system was introduced as standard on Wagoneers and optional on Cherokees. Selec-Trac low range was engaged only when the vehicle was in 4wd since a sequential lockout system within the transfer case prevented low range operation in 2wd mode. A floor-mounted lever controlled engagement in and out of Low range, which was done only when the vehicle was stopped.