Inspection
1. INSPECT OIL PUMP ASSEMBLY

(a) Turn the drive gear with the 2 screwdrivers and make sure that it rotates smoothly.
NOTICE: Be careful not to damage the oil seal lip.
2. INSPECT CLEARANCE OF OIL PUMP ASSEMBLY

(a) Push the driven gear to one side of the body.
(b) Using a feeler gauge, measure the clearance.
Standard body clearance: 0.10 to 0.17 mm (0.0039 to 0.0067 in.) Side clearance: 0.02 to 0.05 mm (0.001 to 0.002 in.) Maximum body clearance: 0.17 mm (0.0067 in.)
If the body clearance is greater than the maximum, replace the oil pump body sub-assembly.

(c) Using a feeler gauge, measure the tip clearance between the driven gear teeth and drive gear teeth.
Standard tip clearance: 0.07 to 0.15 mm (0.0028 to 0.0059 in.) Maximum tip clearance: 0.15 mm (0.0059 in.)
If the tip clearance is greater than the maximum, replace the oil pump body sub-assembly.

(d) Using a straightedge and feeler gauge, measure the side clearance of both gears.
Standard side clearance: 0.02 to 0.05 mm (0.0008 to 0.0020 in.) Maximum side clearance: 0.05 mm (0.0020 in.)
Drive gear thickness: mm (in.) 
Driven gear thickness: mm (in.)
3. INSPECT FRONT OIL PUMP AND GEAR BODY SUBASSEMBLY

(a) Using a dial indicator, measure the inside diameter of the oil pump body bushing.
Standard inside diameter: 38.113 to 38.138 mm (1.50051 to 1.50149 in.) Maximum inside diameter: 38.188 mm (1.50346 in.)
If the inside diameter is greater than the maximum, replace the oil pump body sub-assembly.
4. INSPECT STATOR SHAFT ASSEMBLY

(a) Using a dial indicator, measure the inside diameter of the stator shaft.
Standard inside diameter: 21.500 to 21.526 mm (0.84646 to 0.84748 in.) Maximum inside diameter: 21.57 mm (0.8492 in.)
If the inside diameter is greater than the maximum, replace the stator shaft.
Test yourself
A quick Toyota Sienna quiz: every answer comes with an explanation and a link to the manual page.