I wanted to let you know how very pleased I am with the recent (last June?) work your guys did on my 1991 Ford F-250 diesel with the E40D automatic. I felt that my turbocharged diesel could somehow put more power to the rear tires with some "massaging" of the tranny. Your advice really has paid off! I'm sure you've forgotten by now, but here is what we did and the results I've noticed. We changed the factory chip to a reprogrammed setting. We put a dual disc in the torque converter and we put in an updated valve body with modified shift points. We also added fully synthetic transmission fluid and retrofitted a fluid check stick for convenience. The results have been dramatic. A few days after the work was finished my wife, Terri, drove the truck to Indiana...we really didn't tow anything until December, when we took our 9,000 lb. fifth wheel to Lake Pleasant for a week and then down to Rocky Point, Mexico... The improvements really showed up as I hauled our home around town and then onto the freeways - the shifts off the line were timely and crisp, no more over-revving of the RPMs between gears, no more short shifts causing the engine to start lugging. At no time did the transmission temperature climb over the normal range. Short of buying newer technology, I'm conviced that, with your help, we've made this old truck as strong and powerful as is possible - within my budget. Oh, one more thing. No one mentioned it, but I'm convinced that one of your guys took it upon himself to pound out my bend skid plate under the tranny. It's been bent since I bought the truck in 1997. One more example of the great service and thoughtful help available at Certified Transmissions. So - thank you and your crew for another example of fine, professional work. One Happy Customer, Mark Kuykendall