(Adds details, background)
By Nick Carey
DETROIT, Nov 30 (Reuters) - An influential caucus at the United Auto Workers on Thursday nominated a regional director as candidate for union president at a time when the UAW has struggled to organize auto plants and faces an expanding probe into alleged misuse of funds at training centers funded by Detroit's automakers.
The caucus, named for legendary former UAW president Walter Reuther, nominated Gary Jones, director of the union's region 5 covering 17 Western and Southwestern states, for a four-year term.
The caucus sidestepped a couple of more senior, better-known union figures to opt for Jones.
For the last seven decades, the candidate nominated by the Reuther Caucus has gone on to win election.
The UAW will hold a leadership election in June.
The UAW's next president will have to steer the union through challenging contract negotiations with General Motors Co , Ford Motor Co and Fiat Chrysler Automobiles NV in 2019.
After a boom running from 2010 to record annual sales of 17.55 million units in 2016, new vehicle sales are expected to decline slightly this year, followed by further decreases in 2018 and 2019.
Industry consultant LMC predicts U.S. new vehicle sales will dip to 16.8 million units in 2019, likely portending a much tougher round of contract talks than in 2015 when automakers were on an upswing.
The union is also struggling to add more auto workers to its ranks.
Though UAW membership has crept up since the end of the Great Recession, it is around half of what it was in 1998 and well below a peak of 1.5 million members in 1979. The Detroit automakers and their suppliers have slashed workforces at UAW-represented factories over the past 30 years as they have automated and lost sales to European and Asian rivals.
Earlier this month, workers at a Chinese-owned auto glass plant in southwestern Ohio voted heavily against union representation. The UAW lost the vote at Fuyao Glass Industry Group Co Ltd by a two-to-one margin.
The union also lost a bitterly contested vote at a Nissan Motor Co Ltd plant in Mississippi in August, adding to a decades-long record of failure to organize a major automaker's plant in the U.S. South.
The union's new president will also have to contend with an expanding U.S. Justice Department probe into alleged misuse of funds at the UAW training centers. (Reporting by Nick Carey; editing by Jonathan Oatis)