The HD and SHD NQF and NQG Magna transfer cases (with Allison transmission) have a larger diameter input shaft and input shaft seal. Current transfer case input seal installer GM-42738 will not fit over the increased OD input shaft. The input shaft seal is installed with the input shaft in place and must be driven into the bore flush to case. GM-50648-A will install the new HD / SHD seal, and will also install the past model HD and LD seals. In addition, the new design tool can also be used for the 2015 Magna NQ6 and NQ7 transfer cases for the 31xxN program. For future/new dealers, GM-50648-A will replace GM-42738. New dealers will only receive the one revised tool. In addition, this revision to GM-50648-A will still allow it to be used on the 6L80/6L90 transmission applications it was originally designed for.