[chopper]

Cobra60426 is correct; there are two different size input seals for the Jag rear end, depending whether you have an "early" or "late" rear end. Also, the output seals are different between the two units. However (from just having pulled mine out and replaced all of the bearings and seals) the difference between the inside diameters of the two input seals should be readily apparent to the naked eye. The early unit input shaft has a smaller diameter than the later, so if you have a later unit, the early seal will not fit over the shaft. If you have an early unit, the late seal will fit over the shaft but it should be very obvious that it won't seal.

I'm not familiar with the leather seal. I replaced mine with Federal-Mogul seals. The Haynes manual which I have says to be sure to lubricate the seals with petroleum jelly rather than grease. Apparently they feel that the petroleum jelly will dissolve more readily in the differential fluid and allow the differential fluid to more completely lubricate the seal. I actually used some Parker's O-ring lube when I reassembled mine.

One unusual characteristic which I noted when I disassembled my unit was that the input and output seals were seated completely in the housing, rather than being seated until just flush with the outside of the housing as is usual with domestic vehicle applications. This allowed some corrosion to form on the unprotected surface of the shafts which were outboard of the seal. I had to have one of the output shafts sleeved to restore the sealing surface. If you have the unit out, you may wish to check and ensure that the sealing surface on the input shaft is smooth and will mate properly with the seal. It only takes a small amount of irregularity to wear the seal out in short order. If so, a competent machine shop should be able to procure and press-fit a thin sleeve over the original shaft which will restore the sealing surface. Hope this helps. Having just gone through this, you have my sympathy.

BTW, my undying gratitude to Doug at ERA for his patience in dealing with my one billion and two phone calls to ask for more free advice during this odyssey.