No Fourth Gear

WARNING: This page is about a different car, the 2009 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.

Checks	Causes
4th Clutch Assembly	Inspect for damaged or worn clutch plates. Inspect for damaged piston, piston dam, dam retaining ring, and clutch spring. Inspect for improper selective 4th clutch backing plate retaining ring. Inspect for cut, worn, or damaged turbine shaft fluid seal rings. Inspect for damaged or distorted turbine shaft.
Control Valve Upper Body Assembly	Inspect the 2-3-4 clutch regulator valve and spring for wear or damage.
Front Differential Carrier Assembly	Inspect for damaged gears and bearings.
Front Differential Drive Pinion (w/Transfer Gear) Gear Assembly	Inspect for damaged gears and bearings.