Will an aftermarket driveshaft hit the tranny also? Why or why not?

How much caster will the aftermarket driveline take as compared to the stock driveline?

 

no, it will not hit the tranny as the diameter of the aftermarket shaft is narrower.

regarding how much caster an aftermarket shaft will take, it's hard to say for sure. depending on how much lift you have, what gears you are running and how well the shaft is balanced, it should be able to take at least 5-6° of caster. more lift will create steeper operating angles and a higher ratio gears will spin a lot faster and this will amplify inperfections in the form of vibes.

 

I have the same problems with mine. I have a 2 door with 4.5" of lift and 35's. I haven't ordered mine yet, but I spoke to the guys at Tatton in Utah. They were easy to deal with. I'm only having issues with my rear shaft right now. He said he will send me a new shaft and all hardware for $425 including shipping. That will accomodate up to a 6" lift. He said this will be all I will need. I hope that's right!