just got my truck back from dealer, had the injectors cleaned, thats another thread. Anyways filled it full and now diesel is leaking from the top of the tank by the lines. Maybe the sending unit thingy. I had the lift pump update about a month ago. Could they have not put the tank back together right? It is going into the dealer in the morning. Again!

 

If you'd post your truck in your sig, we could respond more intelligently. For example, I know the fuel tank hookups on my '04 intimately and could comment on that year. I don't know anything about other years.

 

You have two plastic barbed fittings on the top of your tank. You could be leaking fuel out of them if the tank is completely full. It would be a great idea to put a piece of fuel hose on them and T them together and run another hose up high and out of the way and perhaps put a fuel filter on the end of it. It will help keep crud out of the tank. Here is a thread that talks about this...... https://www.dieseltruckresource.com/...d.php?t=117209


Here is a pic of the top of the tank for reference.

 

Since the leak occured after the lift pump was replaced, I would guess that they didn't get the LP lockring seal reinstalled correctly. The engagement for the lockring on the liftpump is pretty tight. If the tech is in a hurry he might not have gotten the lockring completely engaged or gotten the seal set properly.

They may not have gotten the fuel lines engaged properly either. The connections require correct alignment of the male and female ends. If it is not aligned properly, it may leak there as well.

Either one is a relatively simple fix, and I would do the tank vent tube modification as well while the tank is out (What TexasCTD described).