DT-50840 is a double-sided two-function seal installer. One end of DT 50840 is used to install the input shaft double-lip oil seal into the main housing. The seal must be installed to the proper below-flush depth within the housing. The opposing end of the DT 50840 is used to install the input shaft double-lip oil seal into the right side extension housing. This seal is also to be installed below flush to a predetermined depth, and is only installed with the input shaft already installed. The tool is designed to be used with driver handle J 8092 when used to install either seal. Improper installation may lead to seal failure and/or the mixing of transfer case and transmission oils.