Rear Differential Oil Seal

Hey Guys,
I noticed today that my rear differential is leaking where the driveshaft enters the differential.
I have the exact same issue as posted in this article about Previas
http://www.toyotanation.com/forum/85...-pictures.html
My problem is I'm having a hard time finding the correct part for my 1984 van.
Does anyone have any experience with this fix/can help me find the correct part?
Rockauto has 3 different differential pinion seals (sound right?), which seem to the same part number as the previa. Any preferences?
Thanks!

90311-38047 is the part number for all year Toyota Vans, it's available on Amazon for less than $9 so it's not an expensive part. For what it's worth, I just did this job a couple of weeks ago and it is not particularly difficult, just make sure that the nut is re-tightened to exactly (or as close to exactly) as it was before so that the pinion preload stays the same. This thread and this thread gave me all the basic information I needed to get the job done. I wouldn't mess with getting a seal puller, the old seal is going to be stuck in there pretty good and will get mangled coming out; just use a (very) strong flat head screw driver or smaller pry bar and just pry that sucker out of there.