Replacing diff fluid

[Tonestor]

Hi there. I'm glad I found this forum. I recently purchased a 92 FSB. I noticed the rear diff i leaking a little so I wanted to replace the fluid and seal. I bought a Haynes guide and it says the fluid type is different depending on if it is a dana rear axle or a ford rear axle and if it is a limited slip I have to add and additive. I went to the door jamb and it gives and axle code of 19. I also got some numbers off a metal tag on the differential itself. I'm having a hard time online trying to find out what I have. Any help would be appreciated.