Welcome! Was the rear door latch also lubricated? Also perhaps check to make certain that the bolts which secure the spare to tits bracket are tight. Possibly but probably less likely if the noise actually is a squeak it may be coming from the tool kit in the lower right compartment just ahead of the rear door but behind the inside fender well. If it is none of those, some members have had a friend or family member sit inside the rear cargo area while the vehicle is being driven to try to pinpoint where the noise is coming from. Good luck - that sort of noise can be rather irritating!