4 wheel drive problems?

It could be the gear spacer are worn and would need to be replaced. It could also be due to gunk build up in the transfer case which could keep it from sliding back into 2wd position in transfer case. You can run it and just keep trying to get it back to 2wd after drivin a bit, the heat may help it release. If you cannot get it to stop within a few days and cant afford to fix it right away you can disconnect the front drive shaft and just leave it in 4wd until you can afford to put it in the shop. Good luck