This company stands behind it's…
This company stands behind it's warranties. Recently, I bought a 6L80 from them for a 2016 GMC. The local shop installed it. Well, it had a problem in the valve body right from the start. Street Smart sent another transmission and fully reimbursed the additional cost of replacing it. Fortunately, the second unit is functioning well. They also don't front charge you the core costs. As long as you schedule pickup within 30 days, you incur no core fees.