GM-50348 is used to remove and install the valve guide in the head of 3.0L diesel engines. GM-50348-1 is installed into the valve guide and struck with a hammer to remove the guide. To install the new guide, GM-50348-2 is installed over the end of GM-50348-1, and the valve guide is placed onto the pilot of GM-50348-1 under GM-50348-2. The assembly is piloted into the head, and GM-50348-1 is struck with a hammer until GM-50348-2 seats against the head, installing the valve guide flush.