If that's truly the case then it's logical that you should be able to close your eyes with the sound off and still know if your car is understeering or oversteering and whether or not you have REAR traction...So have you closed your eyes and turned off the sound and done it? If not then why not fire the PS3 up and do it intead of continually claiming that you BELIEVE YOU CAN? Are you afraid to admit you're wrong? Why not do it then come back here and explain how it's done? You say that would be ridiculous but it is your logic that says you can feel it through the steering wheel without the aid of visual and audio sensory input.
Coming from someone who doesn't own a wheel.
But FWIW, I just fired up GT5 again last night, and yes I do feel loss of traction with no audio or visual, fairly easily, just as I thought. The only reason why I didn't do it earlier, was because I didn't feel that I had to prove to myself what I already knew. But since I haven't played in a month or so, I decided I would just for fun.
Took an Italia (MR) out with sport tires, got up to speed, jerked the wheel to make a right turn while constantly giving gas to purposely create power oversteer, and I felt my rear end start to slide as the rear tires were losing traction. What I felt on the wheel was the resistance weakened and started to pull a little in the opposite direction until the rear tires started to catch again and the 'pull' stopped. Then I opened my eyes again and did a clean lap on the Eiger track, and I can tell you that there were many times where it looked like I was going straight (or on course), but I felt the same pull on the wheel telling me that I was starting to slide and had to let up on the throttle so that I could gain traction on my rear tires to prevent me from spinning. As I was starting to slide, I looked at my tire temperature on the HUD and sure enough, my tires were starting to warm up.
With that said, do I physically feel the weight transfer in my body? No. Can I sense that the weight is shifting, my rear is sliding and that my rear tires are losing traction through the feel of the feedback from the wheel? Yes.
Coming from someone who doesn't play with a wheel, all you said was that it's not possible to feel traction loss in a video game by feel (only by sight); and coming from someone who has played around 100 hours of GT5 with a wheel, I'm telling you that you can.