Three pump generations of the 5R110W were produced, with varying casting hardness. The Sonnax reaming tool kit used must be matched to the hardness of the pump to extend reamer life and bore finish quality. Carbide tool kit F-36940-TL3C for 36940-03K will provide increased tool life over the standard, high-speed steel reamer tool kit and can be used with all pumps regardless of pump generation.