So I'm not sure what exactly is going on but I have a 07 2500 4x4 with the 48re trans. I am currently running the smarty jr on 40hp level with the timing and tq settings on the highest. Every now and then I would feel a really bad viberation and hear a chaddering sound. The first two times I felt this it almost felt like the truck was being jerked around and it would happen around 2,000rpm (to add it was under 10 degrees outside )Felt like a TC slipping. Now just last night on my way to work it happened again so I decieded I would really get on the thing and in the higher gears i hear a chaddering sound and right away I let off. Now today I couldnt get the truck to do it again. So I dont know what to think.... I called Goerend Brothers and Jeff Garmon today about prices, but now im not so sure what exactly is the problem. Any ideas or input? The truck is throwing no codes either. Thanks in Advance!