47RE 48RE Sonnax 29 spline extreme duty output shaft is the STRONGEST output shaft available for your 47/48RE! This shaft is standard in all Loganbuilt 1500hp builds and beyond. If you are 48 swapping your 4th gen or GM Duramax truck, you will need this shaft to spline up to your oem transfer case. This is a larger diameter than stock shaft for the 2nd and 3rd gen ram. You will need an aftermarket 29 spline transfer case input for those generations, or a manual transmission transfer case input, cut down .875 of an inch.