My nbs Sierra came with a factory kill switch key that worked perfectly well the first year I had the truck. But after that year it stopped working.I was wondering if anybody knows how to reactivate it without haveing to pay gmc a yearly price.
Anybody out there swapped their stock 4l60e for a newer 4l70e or 4l80e is it even possible and is their a significant performance increase with the 4.8 v8