By Kalea Hall

DETROIT, June 1 (Reuters) - Dozens of workers took to picket lines Monday morning at an axle plant in Michigan that supports production of General Motors GM.N trucks, some of the Detroit automaker's most popular and profitable vehicles.

On Sunday, the United Auto Workers announced that workers at the plant in Three Rivers, Michigan, owned ​by Dauch Corp DCH.N, would walk off the job ⁠starting Monday. Dauch, formerly named American Axle, is ​a major supplier of driveline parts.

GM has about two weeks of axle inventory on hand to keep building trucks, according to two people familiar with the matter.

GM ​said it was closely monitoring the situation and "assessing any ​potential impact."

A Dauch spokesperson called the work stoppage "disappointing" in a statement.

"We remain committed to negotiating with the union in good faith and hope to promptly reach a fair agreement," the spokesperson said.

GM shares were down about 2% in afternoon trading Monday. Dauch's stock price was down about 6%.

The Chevrolet Silverado and GMC Sierra pickup trucks, which are made at factories in the U.S., Canada, and Mexico, are GM's top sellers, accounting for nearly one-third of the company's U.S. vehicle sales.

The UAW is pushing for wage increases after employees made ‌sacrifices ⁠to keep the plant open in 2008, according to the union. Top wage earners can make $22 an hour, which is down from ​as much as $29 ​an hour ⁠in 2008, the union said.

In early May, workers voted 98% in favor of ​authorizing a strike if needed.