I had been chasing problems with my truck since the day I bought it used. I went to the dealerships and other transmission shops and everyone was unable to help diagnosis the problem with my shifting problems in the 4l60e transmission. I called B and L transmission and he knew right away of what could be the problem. Even though he did not really find a huge problem with it he went through and did some preventive maintenance on the valve body and modifications. My truck has never drove or shift this good since I bought it after they worked on it. They were very reasonably priced and very prompt to get the work done. When it comes to transmissions these guys know what they are doing and I would recommend them to anyone.