I already have a Mark Williams chromoly driveshaft that runs between a M6 and a Moser 12 bolt rear end. My question is when I convert over to a TH400 can I just have that drive shaft cut and re-balanced or do I need a longer driveshaft? I really don't want to buy a different driveshaft if it isn't necessary.

 

I believe that you will have to have it longer. A good machine shop can make it longer for you. I had to get one that was longer. You might as well get a new one, because the yoke is different also. Good luck.

 

Mine measured in at 47" from the flange of the tranny to the center of u-joint. I'm not sure what that works out to for the driveshaft length, but it's definitely a few inches longer than the stock length.