Is it normal for the transfer case to be difficult to shift? First I tried it while stopped. Then while rolling in N going 5MPH. I have to pull on it pretty hard to get it to engage, to the point I feel like I'm going to break the linkage. Could it be the linkage needs to be lubricated? Is it something in the transfer case? I've already had to fix the linkage once because the plastic clip broke. It's an automatic. Thanks.