first of all, i have a 93 jeep cherokee. and i'm not sure if the low4wd and high4wd are part time or full time. how long can i drive it in part time anyway? and i have problem switching from 2wd to 4wd. whenever i tried to pull the lever, it would easily go to neutral, but it made noises when i tried to put it in 4wd. i'm not sure if it's because the car is old and i never put it in 4wd or if there's any problem with the transfer case stuff. should i go to a shop and have a mechanic check it out?