1. Remove front cover. See FRONT COVER. Using dial indicator, check gear backlash on camshaft gear. Replace camshaft gear if gear backlash exceeds specification. See CAMSHAFT table under ENGINE SPECIFICATIONS.
2. Remove rocker arm assemblies and push rods. See ROCKER ARM ASSEMBLY & PUSH ROD. Remove valve lifters. See VALVE LIFTER.
3. Using dial indicator, check camshaft end play. Replace camshaft thrust plate if camshaft end play exceeds specification. See CAMSHAFT table under ENGINE SPECIFICATIONS.
4. Rotate crankshaft so camshaft timing mark and crankshaft timing mark are aligned. See Fig. 119. Remove camshaft thrust plate bolts. Remove camshaft, camshaft gear and camshaft thrust plate as an assembly.
5. If necessary to remove camshaft gear or camshaft thrust plate from camshaft, use press and support blocks to press camshaft from camshaft gear. Remove camshaft thrust plate from camshaft.