VTD Model

Insert the rear driveshaft into the reduction drive gear and center differential assembly.

Fig 1: Inserting Rear Driveshaft Into Reduction Drive Gear And Center Differential Assembly
Courtesy of SUBARU OF AMERICA, INC.
Using the special tool, measure the distance "A" between the mating surface of extension case and multi-plate clutch (LSD) piston.
ST 398643600 GAUGE

Fig 2: Measuring Distance A Between Mating Surface Of Extension Case And Multi-Plate Clutch (LSD) Piston Using Gauge ST398643600
Courtesy of SUBARU OF AMERICA, INC.
Using the special tool, measure the distance "B" between the mating surface of transmission case and reduction drive gear edge.
ST 398643600 GAUGE

Fig 3: Measuring Distance B Between Mating Surface Of Transmission Case And Reduction Drive Gear Edge Using Gauge ST398643600
Courtesy of SUBARU OF AMERICA, INC.

Formula:

NOTE:

Calculation of "T":
When clearances are 0.05 mm (0.0020 in), select up to four adjusting shims from the table, suitable for clearance value.

When clearances are 0.05 mm (0.0020 in)

T = A - B + 0.40 mm

[T = A - B + 0.0157 in]

When clearances are 0.25 mm (0.0098 in)

T = A - B + 0.20 mm

[T = A - B + 0.0079 in]

T: Shim clearance

A: Distance between extension case edge and rear driveshaft edge

B: Distance between transmission case edge and reduction drive gear edge

T: Shim thickness

0.05 - 0.25 mm (0.0020 - 0.0098 in)

Example:

When, A = 90.50 mm (3.5630 in), B = 90.35 mm (3.5571 in)

Calculation for 0.05 mm (0.0020 in) of clearance

T = 90.50 - 90.35 + 0.4 = 0.55

[T = 3.5630 - 3.5571 + 0.0157 = 0.0216]

Calculation when clearance is 0.25 mm (0.0098 in)

T = 90.50 - 90.35 + 0.2 = 0.35

[T = 3.5630 - 3.5571 + 0.0079 = 0.0138]
Calculation formula for "T" is applied when measuring using ST (398643600 GUAGE). When not using ST, apply
T = (A - "ALPHA" + 0.45 mm) - (B - "BETA") - H

[T = (A - "ALPHA" + 0.0177 in) - (B - "BETA") - H].

T: Thrust needle bearing thickness

A: Distance from end of extension case to end of reduction drive shaft

B: Distance from end of transmission case to end of rear drive shaft

"ALPHA": Collar thickness used when measuring "A"

"BETA": Collar thickness used when measuring "B"

0.45: Gasket thickness (mm)

H: Shim clearance

After calculation, the value of "T" becomes between 0.35 mm (0.0138 in) and 0.55 mm (0.0216 in), therefore select two shims with thickness of 0.2 mm (0.010 in) or one shim with thickness of 0.5 mm (0.020 in).

ADJUSTING SHIM THICKNESS SPECIFICATION

Adjusting shim
Part No.	Thickness mm (in)
33281AA001	0.2 (0.008)
33281AA011	0.5 (0.020)