Since my last post, I've found the proper adjustment I needed and thread locked the nuts to make sure the linkage wouldn't fall off. I lost two before I learned my lesson... I've also replaced the transfer case fluid. It now seems to shift in and out of 4wd much better, however, it needs some coaxing to get back into 2wd. The gentleman who machined a replacement turnbuckle for the linkage gave me a pro tip of spinning the wheels while trying to get back into 2wd. This has done the trick every time. Some gravel, dirt, snow, anything that allows tires to spin will get the transfer case to lock back into 2wd.