Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Power Transfer Unit - Overview: Notes
The AWD system consists of the following:
- Power Transfer Unit (PTU)
- Rear driveshaft
- AWD control module
- Rear axle with coupling device
The Power Transfer Unit (PTU) is a gearbox that attaches to the transmission. The PTU directs power to the rear driveshaft through a helical gear spline coupled to the transmission differential case and hypoid/helical ring gear assembly and pinion set. It supplies torque to the rear axle through the rear driveshaft. The AWD control module is an electronic device which controls the rear axle coupling to apply the torque generated from the Power Transfer Unit (PTU) to the rear wheels when required. On AWD vehicles the intermediate shaft passes through the PTU and engages the differential side gears. The serviceability of the Power Transfer Unit (PTU) is limited to the input shaft seal LH, input shaft seal RH, intermediate shaft seal, transfer case rear seal, cover seal, face seal, vent hose and the output flange deflector. If any internal damage is present the Power Transfer Unit (PTU) must be replaced as a sealed unit.
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.