No, all GM 246 transfer cases are not the same. There are slight variations between different model years and between different vehicles that used the GM 246 transfer case. For example, the 2003-2007 Chevy Silverado and GMC Sierra 1500 both used the GM 246 transfer case, but there are some differences in the way they were built. The biggest difference is that the 2003-2007 Silverado and Sierra 1500 both had an electric shift motor mounted to the side of the transfer case, while later models switched to a push-button shifter inside the cab. Other than that, there are relatively minor differences between different model years and between different vehicles that used the GM 246 transfer case.