When reverse stops working in your 2021 Subaru Forester's CVT (Lineartronic transmission), a specific component in the reverse system has failed while the variable-ratio forward mechanism continues operating. Understanding Subaru's CVT helps diagnose this condition.
Subaru Lineartronic CVT Reverse System
The Forester's Lineartronic CVT uses a planetary gearset with a reverse brake to provide reverse gear. This is separate from the chain and pulley system that provides forward gear ratios. Failure of the reverse brake or its engagement mechanism disables reverse while leaving forward operation intact.
Common Causes
The reverse brake band may be worn, broken, or glazed. The hydraulic servo that applies the reverse brake may have failed. Low CVT fluid prevents proper reverse brake application. The reverse solenoid may have failed. Valve body contamination blocks hydraulic pressure to the reverse circuit.
Diagnosis Steps
Check CVT fluid level and condition—Subaru CVTs require specific fluid and proper level. Note if selecting reverse produces any response—engine rev without movement versus no response at all. Listen for any noises when reverse is selected. Have the TCM scanned for codes even if no warning lights are present.
Warranty and Repair
A 2021 Forester should be within Subaru's powertrain warranty. CVT failures including reverse-specific issues should be covered. Contact your Subaru dealer for diagnosis. Note that Subaru CVTs often require complete replacement rather than internal repair due to the complexity of the units.