I recently had the water pump, pulleys, and tensioner replaced and now I have a vibration that I didn't have before the work being done.

Sometimes the vibration is there on cold startup - idling at 1250rpm, but goes away when the revs drop. If I do a slow pull away from being stopped, there's a vibration at 1200-1300 (give or take a hundred revs). If I do a quick pull away from stop, the vibration isn't noticed (it may occur, but the quick pull away goes past that rpm range quickly). The vibration isn't felt or seemingly present past 1400-1500 revs; it is not felt at highway speeds nor at around town speeds.

I've been using the truck and don't have the time (until next week) to have the indy mechanic have a look. Any thoughts, suggestions (is more information required)?

 

Pop the hood and inspect the alignment between water pump pulley and the other pulleys. I’ve experienced bad water pumps out of the box. The shaft will walk slightly causing serpentine belt alignment issues (vibrations).

To test if this is your issue: Grab a hold of the pulley and check for play by pushing it in and pulling it out. If it moves inward our outward even the slightest the pump should be replaced.

 

Great suggestion, thanks @coors.

 

ISSUE RESOLVED.

Brought the Disco into my mechanic... he found that a couple pieces of the fan blades had broken off (really odd) and there were cracks in some of the other blades, hence the vibration. Additionally, he'll be replacing the fan clutch as he found that it wasn't operating as expected.