A 23 spline transfercase, could a 21 spline be put behind it to double up? I understand the 23 spline input for the tranny. But what is the backside of it, the same as a 21 spline? So could you use a 21 spline doubler behind the 23 spline case or is the input shaft also have more splines where in ingages the gears in the case? I looked around here and Pirate but found nothing really, or my search skills are weak. ![Yup yup :yupyup:](https://board.marlincrawler.com/Smileys/marlin/yupyup.gif)
the backside is whichever you want when you buy the adapter. The coupler mimics the trans output on the backside.