that OD unit appeared in mid 52 and was offered as a retrokit by the factory for 50-51 years though it will retrofit further back than that. the lube in that sucker is GL1 80/90...you can get it from Napa about 15.00 a gallon...only available in gallon size. Do NOT use GL4 and or GL5 as these lubes have shear additives and not good for brass parts. Modern lubes of these rating says they are compatable but if so WHY does the API still have specs on GL1 though GL2 and GL3 are obsolete...answer, because there is a need not to have the additives. The OD unit will also use the GL1. DO NOT get confused with some of the Dodge literature on 10 weight oil....those specs are confused with the fluid drive closed coupler and later in the semi automatic trannys of the era. This tranny is a standard gear box with OD attachment...the long input shaft just allows for use with the fluid coupler...
