The differential is from a cougar or mustang 7.5inch Independent rear suspension modified for a 1 3/4 inch output shaft. The seals used on both sides are skf 32mm x 62mm x 7 mm double lipped rubbler seals. hard to find seals but seals are a Napa 13966 part number cover of differential is a 7.5 inch differential 10 bolt. There is not now or will there ever be a service manual for any of their products.
Taking this apart to change seals involves removing the luggage trunk and moving back at least 6 inches the trike fiberglass body. lot of work for changing the seals. removing the pinion seal is a piece of cake compared to the output shaft seals. Removing the top trunk is almost brain surgery without scratching anything. forget about changing the oil unless you take cover off the differential or want to pump out the oil which defeats even changing it because of any debris that may be resting in the bottom of case. Take the time and remove the cover which involves the same procedure for replacing the seals. Other than that it is a good kit for bike but maintenance headache.