No Third Gear, Slips in Third Gear

WARNING: This page is about a different car, the 2008 Pontiac G5 and 2008 Chevrolet Cobalt. However, it is still accessible from the selected car via links, so may be relevant.

Checks	Causes
Direct Clutch	No apply or slipping
Piston and Seal Assembly (518)	Binding, cracked, or leaking
Clutch Plates	Worn friction or broken splines
Snap Ring (520)	Out of position
Springs (519)	Binding
Direct & Coasting Housing and Input Shaft (520)	Damaged or cracked Restricted feed holes
Housing Retaining and Ball Assembly	Missing or loose
Direct Clutch Fluid Routing	Fluid leak or restriction
Valve Body Gaskets & Spacer Plate Channel Plate & Gasket Driven Sprocket Support	Porosity Misalignment Looseness Fluid Restriction Fluid leak across the channels
Driven Sprocket support Seals	Leaking
Input Shaft	Leaking seals Damaged or misaligned sleeve
2-3 Shift Solenoid Valve (305)	Stuck OFF Leaking
2-3 Accumulator	A leak at a piston seal Channel plate or case porosity
2-3 Accumulator Valve (330)	Stuck
Line Pressure	Low pressure Refer to High or Low Line Pressure .
3-4 Shift Valve (319)	Stuck in upshifted position
PSA (13)	Electrical or hydraulic malfunction