1990 Dodge Ram 90' Dodge Ram 2500 4 wheel drive problem

I didn't realize my 4 wheel was shifted into neutral the last time I drove my Dodge, so I started driving, I live on a dirt road so I was only going about 20 mph or less, when I hit the pavement I realized there was a problem because it wouldnt go faster than 40. I stopped and realized it was my 4 wheel so i tried to get it back into 2wd, and as it usually does, it gave me problems, grinding and whining in every spot I'd move the shifter. After about 10 min of this it finally stopped and went into 2wd. But right after that, I noticed a loud clanging noise from underneath, sounded like change in a metal pan. I'm assuming I sheered off some teeth from the gear and now they're rattling around in the transfer case. But I know nothing really about how to repair or even diagnose this problem....and I dont know how expensive this is going to be... as I dont have much money. So my questions are, do you think that's what happened, and is the cause of the noise, and how do I go about fixing it.

Thanks!!!