CHARLOTTE, N.C. -- The Defenders uncovered groundbreaking information that could impact your ride to the hospital.

For months, NBC Charlotte has been reporting on engine issues affecting about half of Medic’s ambulance fleet. New maintenance records obtained by NBC Charlotte showed some ambulances are breaking down with patients inside.

The records showed several cases in which ambulances had to be towed back to Medic because they weren’t drivable anymore. The ambulances were dealing with mechanical issues such as stalling, engine problems or losing power.

The Defenders showed the findings to Mecklenburg County Commissioner Jim Puckett.

“That is alarming,” said Commissioner Jim Puckett.

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Maintenance records showed dozens of ambulances affected by engine-related issues between 2017 and 2018 -- all while responding to calls, on scene or even transporting patients.

“Anytime you have an ambulance that doesn’t make it to the hospital once they pick up a patient, that’s unacceptable,” Commissioner Puckett told NBC Charlotte.

Early in the investigation, the Defenders asked Medic Deputy Director Jeff Keith if the engine issues have happened while patients were in the ambulance.

“We have not had a single patient care encounter jeopardized by the performance of these ambulances,” Keith told NBC Charlotte.

However, records showed at least three cases already this year where an ambulance transporting a patient was no longer drivable.

RELATED: The Defenders: Engine issues affect 50% of Medic's fleet

“If my wife is in an ambulance, and it breaks down on the side of the road, I am not going to be a happy camper,” Commissioner Puckett said.

NBC Charlotte's investigation also revealed the scope of the engine issues. 28 of Medic’s 64 ambulances ended up on the list for maintenance issues, including some units on the list multiple times.

“One of the great things about what you’re finding is there seems to be a pattern here,” said Commissioner Puckett.

Medic said the issue was specifically affecting ambulances with MaxxForce Engines made by Navistar. NBC Charlotte has learned Navistar is being sued in a class action lawsuit targeting MaxxForce Engines.

“If they were not replacing these engines as quickly as they could, then absolutely you get into the lawsuit,” Commissioner Puckett told NBC Charlotte. “Nobody wants to have concerns over something like their ambulance fleet.”

However, Keith said Navistar has agreed to replace the engines at no cost, which would save taxpayers millions of dollars. Commissioner Puckett said Medic gave a progress report to the county board in June because of the Defenders investigation.

“I think you’re pushing us, I think we are doing it as quickly as responsibly as we can and I think ultimately the public is served,” said Commissioner Puckett.

NBC Charlotte reached out to Navistar multiple times for comment but has not received a response.