The 80 series pinion seals are the same at both diffs. The old number is 90311-38035, it has been replaced by 90311-38047. Again there are not two sizes, but there are 2 different numbers. Either number can be used in either end of the vehicle.
I installed a new OEM pinion seal. The new flange I installed this year has no groves. I put a light film of FIPG 00295-01281 around the outside lip of the seal and on the diff seat. The seat(the part that the seal sits on) had some groves or pits. Maybe (I hope) that is where the leak was.
If it leaks this time I will buy the wife the Land Rolover Discovery that she wants If I am going to have a vehicle that leaks, it might as well be one that was designed to leak
I hope the wife doesn't read this as she would find a tiny drill bit and make the seal leak so she can ride her dream car