I am having this problem on my 3500. This problem started when I figured out that the injection pump kill lever was not being opened all the way by the solenoid. When I fixed this problem I went from making 24-26 pounds of boost to making 40 to 45 pound of boost. Now all of the sudden my transmission will not shift until rpms get really high and it will down shift on its own way to soon. If I have the tc locked up manually with the mystery switch it will shift from 3rd to 2nd at about 56 mph, which really revs up the motor. I have been happy with the transbuddy kit that I installed and I really like to be able to lock up in any gear. I am wondering if the cause of this is a internal leak of somekind. Any input or solution would really be appreciated, as I have many loads of hay to move next week!!! Oo.