My suv acts like it is halfway stuck in 4wd

Well, certainly there is a drive train problem of some kind -- whether it has to do with the all wheel drive system or just the automatic transmission itself is unclear and requires hands on testing to determine. It definitely does sound like something is binding, and could definitely be a transfer case related concern. Check all four of your tires -- are they the same model, size and have the same amount of tread depth? What often happens is that dissimilar tires can put abnormal strain on the transfer case and all wheel drive system, causing damage. Too hard to say and definitely requires a physical inspection to know what's going on.