[Jac Mac]

If its an earlier C4 with dipstick tube that push's into trans body rather than bolting onto pan it could be for that. A lot of trans kits have enough o-rings to serve all variations/updates, but my guess is either dip stick or speedo cable end. Can you not contact the shop guy on After Hours #? No O-rings on input shaft of that size that I can think of and nothing else that can be fitted after assy..