CHICAGO (CBS) —Thousands of GM drivers without wheels for nearly a month.

They can’t find a critical car part.

There may not be a major GM assembly plant in the immediate area, but the effect of the auto workers nearly month long strike against the company is starting to inconvenience many Chicagoans.

CBS 2’s Vince Gerasole explains why there’s a shortage of replacements.

“I never imagined I would be waiting four weeks for a part,” said Robert Zambrino of Carol Stream. He said he would like to talk to us in his 2015 Chevy Malibu LT. But he can’t.

“I’ve been in contact with General Motors at least a half dozen times. They stopped returning my call at some point,” Zambrino said.

Zambrino needs a timing valve. Dealers said for this part alone, 6,000 nationwide are on back order. It’s the ripple effects of the UAW strike against the auto giant, which has led GM to make additional layoffs throughout their parts and distribution services.

“It’s impacting us in a negative way,” said Robert Carrasquillo of C and W Auto Body. “It’s rough getting parts here.”

At the shop, GM vehicles have been sitting in the garage for weeks, while Carrasquillo hunts nationwide for replacement parts without much luck.

“We can’t get cars back to customers in a timely manner,” he said.  “If you had a GM vehicle, I’d tell you not to leave the car here.”

It’s estimated dealers have enough new car inventory to last 90 days, but parts are a different story with more immediate impact. Zambrino is getting around, in a 45-year-old two-seater without heat, has him hot under the collar.

“If they want to have a beef with their employees, that’s fine. But when it starts to trickle down to their customers, I think it’s time to make some serious decisions.”

Dealers tell CBS 2 this is just the tip of the iceberg. Many said if the strike stretches into next week, the impact will be much worse.

Analysts say locally-based Tenneco, a parts manufacturer employing 100 in Skokie, is losing about one million dollars a day because of the strike.