I finally fixed all the oil leaks last week and this week I got a fuel leak. The leak seems to be from the fuel lines coming out of the tank. There rubber hoses from the top of the fuel tank which are clamped to metal tubing. The metal tubing runs along the frame rail where one connects to lift pump and then other continues to a union which connects to rubber hoses which goes to the engine bay. Do I need to buy these new lines from GM or can I modify something?I know the tank has to come down in order to reach the hoses on top. Has anybody changed these hoses?:(

Any Diesel fuel compatable rubber hose will work, does not have to come special from GM

Thanks for the info Turbine Doc but I think I didn't explain myself well. I had a look this morning and the leak is coming from the top of the fuel tank. The rubber hoses which come down from the tank look like the oil cooling hoses the same system. They are clamped on steel line which go all the way to front of the truck.
I guess I could buy rubber hoses and steel tubing and make my own. Buying it from the dealer would be alot quicker but I'm sure their expensive.
I'll give it try and let you know.

Finally got around to work on the truck. The problem was the fuel gauge lines which come out of the fuel tank. They were rusted it out. Hundred fifty dollars and another 200 for the fuel tank. Replaced it today and truck is happy again and so is my wife no more diesel fuel smell in the front of the house.
Is it normal for the fuel cap to let out pressure when I open it? I find it does it quite often. It did it before I changed the tank also. When it was leaking I would leave the cap a little loose and it wouldn't leak. :)