Los Angeles based DIESEL MACHINE was the side activity of HALFORD guitarist Pat Lachman. Before his term with HALFORD, Lachman had been involved with STATE OF THE ART in league with his brother, erstwhile GARGOYLE vocalist Tim Lachman, future RAISED BY ALIENS bassist Alex Sarabia and drummer Dennis Kelly. The Lachman siblings would later be found in both ERROR 7 and ELEVENTH HOUR with both of these acts donating tracks to an IRON MAIDEN tribute album.

Initially titled DIESEL, Lachman would forge a union during 1996 with WORLD IN PAIN vocalist A.J. Cavalier and Canadian drummer Shane Gaalaas, the latter having a wealth of Hard Rock credentials to his name including high profile stints with YNGWIE MALMSTEEN, ARTENSION, ULI JON ROTH and the MICHAEL SCHENKER GROUP. This trio cut a six track demo which elicited strong praise from the Metal media. Shortly after the band was rounded out by the induction of DEVILUTION and RECIPIENTS OF DEATH bassist Rick Gonzales.

In 1999 DIESEL MACHINE donated their heavyweight rendition of 'The Thing That Should Not Be' to the Dwell Records METALLICA tribute album 'Overload: Tribute To Metallica'. Relying on their own endeavours DIESEL MACHINE entered the recording studio self financing their debut album 'Torture Test'. The record would be mixed by Pat Regan and released by the German SPV label in February 2000. DIESEL MACHINE bassist Rich Gonzales suffered a major accident in August of 2002, his Harley Davidson being hit by a car. The four stringer was in a coma for two days but would make a recovery.

DIESEL MACHINE gigs had been sporadic due to the priorities afforded by Lachman to HALFORD and Gaalaas to his various band pursuits. However, renewed impetus was given to the band once Rob Halford announced his intention to rejoin JUDAS PRIEST. In November of 2004 A.J. Cavalier joined Chicago Alt-Metal band SOIL as their new frontman. Meantime, Patrick Lachman found a new home fronting the high profile DAMAGEPLAN band assembled by former PANTERA members guitarist Darrell 'Dimebag' Abbott and drummer Vinnie Paul. DAMAGEPLAN released a highly acclaimed album before being stopped in their tracks by the onstage murder of Dimebag in December 2004. Shane Gaalaas issued his second solo album 'Hinge' in April 2005.

In August Patrick Lachman unveiled his new band MERCY CLINIC. The band line-up comprised guitarists Brian Harrah of PROFESSIONAL MURDER MUSIC and Josh Stinson from DRIST, bassist Steed Najera of TRIPLE SEVEN and the DANZIG and JERRY CANTRELL credited drummer Bevan Davies.