After reports of employees collecting unusually high amounts of overtime, T officials said Monday they were working on an OT overhaul.

A seven-member team of auditors has been studying how T employees are paid overtime, T officials said, adding that the focus is on 2014 and 2015, but that auditors may dig into more historical data as well.

They expect to finish their review in 4-6 weeks and issue a report on whether overtime is being managed well, whether it’s used for the right reasons and whether it is well-documented.

The audit comes after news surfaced that about one in four T employees took home more than $100,000 in 2015 in gross pay boosted by overtime, and that one employee earned more than $315,000 last year, in part by clocking 2,600 hours of overtime and adding more than $170,000 to his base pay.

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According to union contracts, overtime for T employees kicks in when they work more than eight hours in one day. Last year, the T paid $31.8 million in overtime to employees who had worked fewer than 40 hours in a week, 43 percent of all overtime payments, according to a report.

Officials said the T was working with unions to re-assess that overtime structure.

“To be clear, they bargained for that and prior T administrations agreed to it so that’s why they get it, but it’s a substantial cost,” Transportation Secretary Stephanie Pollack told reporters Monday.

The T is also focusing on reining in absenteeism among T workers, MBTA Chief Administrator Brian Shortsleeve said. The T pays overtime for workers who fill in for another employee who has taken an unscheduled day off.

Following advice from consultants, the T is also starting up a new process to manage requests for days off and is pursuing a third-party to run it, Shortsleeve said.

“We’re hoping as we get into January and February that you’ll see some really significant changes,” he said.

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