Chevrolet Silverado / GMC Sierra. Service manual — part 587

Fig. 35: Measuring Clearance Between Gear Teeth & Oil Pump Housing
Courtesy of GENERAL MOTORS CORP.

3. Use a feeler gauge to measure the clearance between the gear teeth and the oil pump

housing. The production clearance is 0.125-0.221 mm (0.0049-0.0087 in) and the service

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Mechanical - 6.6L - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

limit is 0.221 mm (0.0087 in).

4. Replace the oil pump assembly if the clearance exceeds the service limit.

Fig. 36: Measuring Clearance Between Side Of Gear & Cover
Courtesy of GENERAL MOTORS CORP.

5. Use a feeler gauge and a straightedge to measure the clearance between the side of the gear

and the cover. The production clearance is 0.064-0.109 mm (0.0025-0.0043 in) and the

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Mechanical - 6.6L - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

service limit is 0.109 mm (0.0043 in).

6. Replace the oil pump assembly if the clearance exceeds the service limit.

Fig. 37: View Of Driven Gear Shaft & Bushing Measurements
Courtesy of GENERAL MOTORS CORP.

7. Calculate the driven gear shaft to bushing clearance.

1. Measure the driven gear shaft outside diameter. The production specification is

19.947-19.960 mm (0.7853-0.7858 in) and the service limit is 19.86 mm (0.7819 in).

2. Measure the driven gear bushing inside diameter. The production value is 20 mm

(0.7874 in).

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Mechanical - 6.6L - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

3. Calculate the driven gear shaft to bushing clearance. The service limit is 0.14 mm

(0.0055 in)

8. Replace the oil pump assembly if the clearance exceeds the service limit.

Fig. 38: View Of Oil Pump Gear Cover & Bolts
Courtesy of GENERAL MOTORS CORP.

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Mechanical - 6.6L - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado