Sonnax manual shift shaft kit 38511-03K for the GM 4L80-E is an early model ’91–’94 manual shift shaft that retrofits to a late-model ’95-later manual shaft detent lever, allowing the late-model case and detent lever to be used in early-models. This helps rebuilders use late model cores to rebuild into early-model units. This kit is a more economical solution than the OE manual shift shaft and detent lever kit, without the added cost for such additional components as the OE lever, pin and shaft seal. These parts are rarely used during the rebuild. The manual shift shaft and fasteners have been yellow zinc plated for corrosion resistance to road salt and other environmental contaminates. The flange face of the nuts is serrated for better holding capacity.