"Five stars. I drove almost four and a half hours from northern Michigan to National Transmission for torque converter issues on my 2015 GMC Sierra. Instead of just replacing the converter, they thoroughly inspected the transmission and took care of additional work to help prevent future problems. The truck now runs better than it did when it was new. The service and workmanship were outstanding. I’m very satisfied and highly recommend them. I only wish there was a shop this good closer to home."