prt number for the transfer case rear seal on 231

well im buying a trans out of a 93 so im keeping my np231. the rear out put seal for my drive shaft is tore and pukes fluid. does anybody have a part number for it? oreillys can not find it in there catalog:twak:

My parts catalog indicates you want part #15 on figure 21M-1100, which is MOPAR part number 4638 904, description SEAL, Transfer Case Rear Stamped NPG 16104. 4wdtruck has it for $4.06 along with a full exploded diagram of the np231, which is quite useful: http://4wdtruck.com/jeepparts/index.php?main_page=index&cPath=551_557#30