My 3/8 fittings do not rub the shock towers, even with the new ARO towers. After gluing the fitting around the diff cup, grind a bit off the outside of the fitting if it is rubbing. You can put the diff cup into your drill so the end with the fitting is sticking out, spin it and touch the outside with sandpaper. If you need to take a lot off, use a file instead of sandpaper. It works pretty good. Someone else here gave me that trick, wish I remembered who so I could give them credit.