At approximately 18,000 miles the engine on my brand new GMC seized up while I was taking 4 of my employees Downtown Detroit. The engine stopped as I was merging into 3 lanes of traffic from the left lane. I had to cross 3 lanes during rush hour almost resulting in a major accident. Then I had to wait 2 months to replace the engine. 25,000 miles later, the second engine seized up while I was transporting my father between nursing home facilities. The third engine, I have recently been told only has a 12,000 mile warranty. I have requested that GM give me a 60,000 mile warranty on this 3rd engine and they refuse as it is past 30 days since the 3rd engine was installed. I should be getting a new truck, but I am just asking for a warranty. This is a known problem, which obviously has not been fixed. In both instances, there were no indications of a problem until the engine stopped running. The first time, I had 4 of my employees, which I was responsible for, in my car merging in the left lane with no engine power during rush hour, putting everyone at great risk, including other cars and people. The 2nd time, I had my [XXX] father in transit between nursing home facilities. This obviously was a very stressful event for both of us. Both of the dealerships that replaced the engines confirmed that they have been seeing this same issue in many other GM trucks. I personally know of 3 people that this has happened to. In both cases, I had to wait weeks to replace the engine because of the backlog to order the engine for other people. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)