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.
2018 Buick Envision BaseFACTORY OEM SERVICE PROCEDURE
Power Transfer Unit/Transfer Case - AAM
- Specifications
- Component Locator
- Diagnostic Information and Procedures
- Repair Instructions - On Vehicle
- Drain Plug Replacement
- Fill Plug Replacement
- Intermediate Drive Shaft Replacement
- Power Transfer Unit Cover to Intermediate Drive Shaft Seal Replacement
- Output Shaft Seal Replacement
- Intermediate Drive Shaft Bearing Replacement
- Power Transfer Unit Face Seal Replacement
- Transfer Case Bracket Replacement
- Transmission Brace Replacement
- Power Transfer Unit Case Replacement
- Repair Instructions - Off Vehicle
- Power Transfer Unit Case Disassemble
- Power Transfer Unit Case Holding Fixture Installation
- Power Transfer Unit Oil Fill Plug, Oil Drain Plug, and Vent Hose Connector Removal
- Power Transfer Unit Intermediate Drive Shaft Components Removal
- Power Transfer Unit Rear Seals Removal
- Power Transfer Unit Extension Housing Removal
- Power Transfer Unit Input Shaft, Idler Shaft, and Idler Shaft Tube Removal
- Power Transfer Unit Alignment Sleeve, Face Seal, Input Shaft Bearing Race, Idler Gear Bearing Race and Shim, and Idler Gear Shaft Tube Seal Removal
- Power Transfer Unit Idler Shaft Bearing Race, Input Shaft Bearing Race and Input Shaft Seal Removal
- Power Transfer Unit Case Cleaning and Inspection
- Power Transfer Unit Case Assemble
- Power Transfer Unit Idler Gear Shaft Tube and O-ring, Input Shaft Bearing Race and Shim, and Idler Gear Shaft Bearing Race and Shim Installation
- Power Transfer Unit Alignment Sleeve, Face Seal, Input Shaft Bearing Race, Idler Gear Bearing Race and Shim, and Idler Gear Shaft Tube Seal Installation
- Power Transfer Unit Input Shaft and Idler Shaft Installation
- Power Transfer Unit Extension Housing Installation
- Power Transfer Unit Propeller Shaft Seal and Rear Output Shaft Seal Installation
- Power Transfer Unit Intermediate Drive Shaft Components Installation
- Power Transfer Unit Cover-to-Intermediate Drive Shaft Seal Installation
- Power Transfer Unit Oil Fill Plug, Oil Drain Plug, and Vent Hose Connector Installation
- Power Transfer Unit Case Holding Fixture Removal
- Power Transfer Unit Case Disassemble
- Description and Operation
- Special Tools and Equipment
Factory Service Tools
Use the Manual With the Right Hardware
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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.
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