Thanks...I think it is the back, now, too. I found a seal kit I bought, and the nameplate says it's a "sperry-vickers", so now I have to see if I have the right parts, decide if I want to do the front seal (it doesn't seem to be leaking), and then get started. I think I will not do the front seal yet, since I would need to get the pulley off and I don't have a puller. I'll post some pics!
1980 300SD (daily driver), 1981 300D (Inca Red)