GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2008 🢒 Express 🢒 Transmission/Transaxle 🢒 Automatic Transmission - 4L80-E/4L85-E 🢒 Loss of Drive

Checks

Cause

Torque Converter (1)
    • Broken lug or failed lug welds
    • Sheared lug bolts
    • Worn turbine shaft splines
    • Low oil
    • The pump hub is cracked, scored, or broken.
    • Internal failure
    • Failure of the closure weld
    • The cover is cracked at a lug weld.

Pump (203)
    • The pump is seized.
    • The pump gears are broken.

Case Extension Seal (20)

The seal is missing, damaged, or displaced.

Orifice Plate

The plate is missing or leaking around the edge.

Gasket (6)

Damaged

Oil Transfer Hole Cup Plug

The plug is leaking or missing.

Seals (503)

The seals are damaged or missing.

Housing (504)

The housing is broken.

Roller Clutch (512)

The clutch is worn, broken, or locked.

Carrier (514)

Broken

Pinions (518)
    • Broken free from the pilot
    • Spalled pins or pinions
    • Plugged pinion pin holes
    • Worn thrust washers
    • Lack of lube

Bearing (513)

The bearing is broken.

Roller Clutch (644)
    • The clutch is worn, broken, or locked.
    • Lack of lube

Turbine Shaft (502)

The shaft or the splines are broken.

Forward Clutch Components

  • Seals (603, 604, 605)

Nicked or cut

  • Checkball

Leaking

  • Piston (606)

Cracked or jammed

  • Housing (602)

Cracked

  • Friction Plates (611)

The plates are burned or the splines are worn.

  • Reaction Plates (610)

The plates are worn or the splines are worn.

  • Spring Assembly (607)

Jammed

  • Driving Hub (615)

Broken

  • Retainer Ring (616)

The ring is not seated.

  • Driven Hub (613)

The gear teeth are worn.

Rear Gear Set

  • Pinions (655)

Broken or spalled

  • Pinion Pins (656)

Broken or spalled

  • Needle Bearings (654)

Broken or spalled

  • Sun Gear (649)

Broken or spalled

  • Pinion Thrust Washers (652)

Worn

  • Rear Internal Gear (666)

Broken or spalled

  • Front Internal Gear (661)

Broken or spalled

  • Turbine Shaft Ball Seal

Ineffective

  • Mainshaft (662)

The shaft or the splines are broken.

  • Fluid Pressure

Too low