The GMT355 twins Chevrolet Colorado and GMC Canyon have been out for six years and are due for a refresh. A next-generation global Colorado test mule was recently spotted during a winter drive, but from the looks of it, the mid-sized tester shares more in common with its foreign-spec siblings (the Isuzu D-Max and Holden Colorado) than its U.S. counterparts. The spied Colorado mule was powered by a diesel engine and sports few notable changes other than a slightly revised front bumper and shorter headlight profile.

According to’s sources however, the U.S. may not receive a successor to the current Colorado/Canyon. Sales have slumped and GM’s Shreveport, Louisiana plant, home to the Colorado, Canyon, and Hummer H3/H3T, is slated for closure by June 2012 with no indication as to where production would be moved. Meanwhile, GM has borrowed $445 million to expand its Colorado producing facility in Thailand; the hefty loan package was sourced from three Thai banks.

To see the spy shots, visit the link below.