Upwards of 35 lawsuits have been filed across the U.S., alleging a broad conspiracy among manufacturers to fix and inflate prices of oil, air, fuel and transmission filters. The conspiracy supposedly began in 1999 and continued into this year.

"Through meetings at industry events and elsewhere, and (through) the exchange of confidential pricing materials, defendants unlawfully agreed to the magnitude and timing of price increases," one of the suits asserts.

Filed by automotive parts distributors, service outlets and vehicle dealers, the suits are against Champion Laboratories, Purolator Filters, Honeywell International, Wix Filtration Products, Cummins Filtration, the Donaldson Company, Baldwin Filters, Bosch, MANN + Hummel, Arvin Meritor, United Components and The Carlyle Group.

The suits, which have been filed in New Jersey, Connecticut, Illinois and Tennessee, allege "a massive conspiracy among the largest manufacturers of oil, air, fuel and transmission filters in the aftermarket ... to fix, raise, maintain or stabilize prices, rig bids, and allocate customers for filters in the United States."

According to one suit, a confidential informant who was a senior sales executive employed by two of the companies, says the defendants conspired and agreed to coordinate prices, rig bids and allocate customers.

Former Champion manager William Burch has admitted to the conspiracy, according to the suit filed in federal court in Newark, N.J., by Central Warehouse Sales, a Scranton, Pa., filter distributor.

Burch "testified in an Illinois court proceeding that he was asked to participate in fixing prices," according to an attorney who represents Central Warehouse.

Burch tape-recorded his conversations with other people in the industry, and copies of those tapes have been sent to the U.S. Justice Department, the attorney said. Champion sued Burch in 2006 and accused him of submitting false expense account charges, which he denied.

A spokesman for Honeywell Transportation Systems was quoted by one New Jersey newspaper as saying the company takes the allegations "very seriously."

"Compliance with anti-trust laws is an important part of Honeywells code of conduct and training, and is strictly enforced throughout our businesses," he said. "Any claim of misconduct by a Honeywell employee or groups of employees is taken very seriously and investigated rigorously to ensure that the highest levels of business practice standards are being met."