Was the quad cab SRT-10 equipped with an automatic transmission because it simply shouldn't have a manual transmission, because of the massive drive shaft length? I had a T56 installed in my SRT-10, and had vibration occur around 100MPH. But, if I'd blow past that it smoothed out around 110 or 115 and roared. Eventually the input shaft bent slightly, a tooth was lost, & the input housing developed a fracture. I then had tick performance give me an upgrade (T6060), which fit much better and tighter than the T56, but upon break-in and a slow acceleration to 100MPH the vibration still exists. I can elaborate, but I just wanted to post this and see if anyone has had any experience with this issue. Thanks in advance for any feedback.