so driving it home is out of the question right? how much would it cost to replace the chain if I do it myself? How many parts will I need to change with it? Thanks for the info man I really apprecaite your response!
Whether it's safe to drive depends on whether the chain itself is loose or just has a broken guide. If the guide is broken, then the chain is slapping against the timing cover, which has a water jacket - if it wears through (and if you give it enough time it certainly will) you'll mix your oil and coolant and then you'll HAVE to get it towed - risky, sure, but if the fellow hasn't been driving around on it much you'll probably make it. If the chain itself is physically loose, either due to stretching or a busted tensioner, then you run the risk of damaging your valves (or if it breaks, potentially destroying them), and in that case I wouldn't drive it at all unless you're ready to rebuild the head as well as replace the timing chain.
Before you tear into the timing, you'll want to get a copy of the Factory Service Manual (check the links up top) and a Chiltons or Haynes manual too. They'll break down the timing chain service in detail, but if I remember right you'll pull the fan and belts, break the crank pulley bolt free, drain the oil, drain and remove the radiator, remove the intake plenum and exhaust manifold, remove the valve cover, remove the head, detach (but don't remove) the AC and power steering pump, remove the water pump, remove the timing chain cover, replace the chain and guides, put it all back together. It's an all day job if you know what you're doing, I know it would take me at least two, more if I hit any snags.
As long as you have the head off, consider taking it to an automotive machine shop and having it checked out. Rebuilding the head just for the heck of it is not completely out of the question considering what a PITA it is to remove it, and the unknown history of the truck. I'd get the fuel injectors cleaned and balanced too. A timing chain set and top end kit from engnbldr.com will have all the gaskets you need, order new head bolts too just to be safe. The guy at engnbldr knows his stuff and likes to answer questions, so don't be afraid to talk his ear off.
Cost wise, I spent under $200 pulling and replacing the head on my 22re, and that included the top end gasket kit and getting my head checked out at the shop. You'll be buying a timing set as well (and maybe a timing chain), but you'll still probably come in under $400 including the fresh oil and coolant and all the other various sundries. By comparison, a shop will probably charge you at least $1000.
