I just installed a used Warn overdrive unit that i bought at Carlisle. and on the first test today In overdrive is working fine. But in direct it will move for a little bit and then on differnet torque load it pops out of gear and grinds. The guy i bought it from said it came out of a running jeep and worked fine. ( i trust him, because he is local to me and invited me to his house anytime to look at jeeps which i have done. and go trailriding with him. I dont think he would do this if he sold me a junk part) I have tried tightening the detent on the shifter and it worked better but still poped out of gear. I'm not sure if im missing a part like a syncro etc. Should i try tightening the detent more? I did see a video saying to measure the distance between the planatery gear and t-case. They said it should be 0.677 mine was 0.55. I dont know how crucial this is or what to do if its wrong. Would that make it grind?