Power Transfer Unit - Overview. Description and Operation

The all-wheel drive system consists of the following components:

• Power Transfer Unit (PTU)
• Rear Driveshaft
• AWD Control Module
• Rear axle with coupling device

The Power Transfer Unit (PTU) is a gear reduction unit that is mounted to the transmission. The PTU directs power to the rear driveshaft through a helical gear connected to the transmission differential case and a hypoid/spiral bevel ring gear and pinion assembly. It transmits torque to the rear axle through the rear driveshaft. The All-Wheel Drive Control Module is an electronic device that controls the rear axle clutch to apply the torque produced by the Power Transfer Unit (PTU) to the rear wheels as required. On all-wheel drive vehicles, the intermediate shaft passes through the PTU and meshes with the differential side gears. The Power Transfer Unit (PTU) serviceable components are limited to the left primary shaft seal, right input shaft seal, intermediate shaft seal, rear transfer case seal, cover seal, face seal, vent hose and output flange deflector. If internal damage is found, the Power Transfer Unit (PTU) must be replaced as a sealed unit.

Power Transfer Unit (PTU) - Exploded View

1. 1
   Output Flange Nut
2. 2
   Output Flange
3. 3
   Deflector
4. 4
   Rear Transfer Case Seal
5. 5
   Output Shaft Outer Tapered Roller Bearing
6. 6
   Output Shaft Outer Tapered Roller Bearing Race
7. 7
   LH Input Shaft Seal
8. 8
   Transfer Case Vent
9. 9
   Power Transfer Unit (PTU) Case
10. 10
    Input Shaft
11. 11
    Input Shaft Bushing
12. 12
    Input Shaft Outer Bearing
13. 13
    Input Shaft Outer Bearing Washer
14. 14
    Cover O-ring
15. 15
    PTU Cover
16. 16
    PTU Cover Bolts (9)
17. 17
    Intermediate Shaft Seal
18. 18
    PTU Fill Plug
19. 19
    Right Input Shaft Seal
20. 20
    Output Shaft
21. 21
    Output Shaft Inner Tapered Roller Bearing
22. 22
    Output Shaft Inner Tapered Roller Bearing Washer
23. 23
    PTU Drain Plug
24. 24
    Face Seal
25. 25
    Input Shaft Inner Bearing
26. 26
    Input Shaft Bearing Inner Washer
27. 27
    Identification Tag