With Brent Mydland only months into his 11-year tenure and with new songs from the forthcoming Go to Heaven entering the rotation, the Grateful Dead that pulled into Chicago’s Uptown Theatre on Dec. 3, 1979, was a band in transition and on a mission.

That mission was accomplished on this evening, which achieved official-release status with the appearance of Dave’s Picks Volume 31, a three-disc affair that presents the entire show along with three tracks from the following evening. The gem of this triptych is “Jam,” a 10-minute, on-the-fly composition that demonstrates the new version of the band was already deep into ensemble groupthink mode. Driven by Mydland, guitarist Jerry Garcia and bassist Phil Lesh, this aural exploration never gets lost as it bounces along on an up-tempo groove that makes the listener wish the Dead had thrown caution more often in the last half of its career.

The main event opens with the first of four Go to Heaventracks and the nascent “Alabama Getaway” runs for seven full minutes. The entire first set is a speeding ticket waiting for anyone who plays this in the car as the band revs up outstanding versions of “Brown-Eyed Women,” “It’s All Over Now,” “Jack-A-Row” and seven other tracks both new (an 11-minute “Althea”) and old (Marty Robbins’ “El Paso”) that serve as a reminder first sets used to occasionally outshine second helpings.

But this entire show sparkles and is limited only by Garcia’s ragged-out voice, which he struggles to control making for some difficult-to-swallow vocal moments, as on “Wharf Rat.” There’s also a jarring, low-quality audience patch that mars an otherwise-outstanding, 27-minute tour through “Scarlet Begonias”->“Fire on the Mountain.” 

This band-aid notwithstanding, the sound is as sterling as the musical performance. Even “Space,” a two-minute, full-band deluge is spectacular as it leads unexpectedly into “Lost Sailor,” which morphs into an embryonic “Saint of Circumstance” sporting scratch lyrics that were thankfully revised.

“Truckin’” is a monster that ends with a build-and-release crescendo so intense it signaled the concert’s end. The band sounds exhausted on the “Johnny B. Goode” encore that follows, but this in-concert recording leaves no doubt everyone left Chicago that evening feeling really fine.