"We're going to be looking at every inch of this union to make sure we embrace tight controls," acting head Rory Gamble told Reuters. "We need to make sure we have standards that stop this thing from happening again."
Gamble's comments came after retired UAW vice president Joe Ashton was charged with conspiracy on Wednesday. Ashton is accused of getting thousands of dollars in kickbacks from a contractor who made watches for union members. The 58,000 watches are still in storage five years later.
Gamble said he would propose a new set of "very strict rules" to the UAW board on Thursday to stem corruption.
"We need to get away from that wall of silence that seems to have surrounded some of this stuff," Gamble said, according to Reuters.
UAW President Gary Jones passed the torch (temporarily) to Gamble to take a leave of absence amid the escalating federal corruption probe.
In August, agents from the FBI, IRS and Labor Department raided Jones' home, gathering evidence in their probe. In September, UAW leaders decided to strike against General Motors in a walkout that lasted for more than a month.
Jones has not been charged with any crimes. Prosecutors charged one of his top associates, Edward "Nick" Robinson, with conspiracy to embezzle union funds and conspiracy to defraud the U.S., making Robinson the 12th person charged in the investigation.
The Associated Press contributed to this report.