was driving (04 exped e.b.4x4)on highway bout 45-55 mph and suddenly, grinding noise from the front end followed by a loud pop...........

took to dealer said was the rear end....told em problem up front, persisted and replaced the rear end ring and pinion....

picked car up, and same thing....took it back, seems the vacume line for the hub was leaking causing to not engage right.....

they gonna replace the line, but im worried something broke, or damaged....they saying they gonna test drive in 4x4 and 2x4 make sure all is ok.....

but after a lound grinding and a pop, im not at ease with just a vacume line replacement....my logic tells me somehting broke/craked/fractured/bent.....any ideas...suggestions would be appreciated....truck under full waranty.....

not feeling to confident after a rear end replacement when it was up front vacum line leak all along....know what i mean??????

 

I would be suspicious as well. The only problem is if the dealer replaces a part that isn't broken and Ford calls the part back for inspection, which they most likely will, then the dealer will get charged back for not only the part but also the labor.
I have had many vehicles that i would have loved to install more parts to ensure the job was done right, but Ford is ultimately paying the bill and they make the rules.
I would drive it and if it has even the slighted bit of noise i would take it back.

If you are in Orlando try http://www.mobileoval.com . They are Ford specialists.