Is my 203\'s chain slipping? I was doing some towing last weekend with my '77 suburban. It's a 400/TH350/np203. The 203 has been converted to part time using some unknown kit by the previous owner. Anyway, I got into a big snow storm climbing the hill outside McCall, Idaho. Things got a little squirrely, so I turned in the hubs, and put it in 4 high. About 1/2 way up the hill, I start getting a loud banging noise every 5-10 seconds. Like the front end is going to fall out kinda banging. Only does it when the transfer case is shifted into 4 and under a load, like pulling the trailer. I am thinking the chain in the 203 is slipping? Sound right?