common to sa mga pick-ups, because of the light rear load on the tires. happened to me when we where in Cebu, we went to TOP and nearing the place there was this old tamaraw going up backwards ala front wheel drive effect. so had to stop in front of the house of Osmena siguro, it is one of the tallest part of the road, yun had to shift to 4L because the rear tires just slipped even with LSD na. tires were General Grabber AT.