* Reverse Gear Problems within the Transmission: This is the most common cause. The reverse gear teeth might be worn, broken, or improperly engaged. This often requires a transmission rebuild or replacement.
* Reverse Switch or Solenoid (if applicable): Some automatic transmissions use a reverse switch or solenoid to engage reverse. A faulty component could prevent reverse from engaging, even if the transmission itself is fine. This is a relatively inexpensive part to replace.
* Transmission Linkage: If it's an automatic, there's a linkage system (or cables in some cases) connecting the shifter to the transmission. A broken or dislodged linkage component could prevent reverse from engaging. This is usually easier and cheaper to fix than internal transmission issues.
* Low Transmission Fluid: While less likely to cause *only* reverse to fail, low fluid can impact gear engagement. Check the transmission fluid level and condition. If it's low or dirty, it should be addressed.
* Valve Body Issues (Automatic): The valve body controls the flow of fluid within the transmission. A problem within the valve body could prevent reverse from engaging.
What you should do:
1. Check the Transmission Fluid: Make sure the fluid level is correct and the fluid itself is clean and red (not brown or burnt). Low fluid can cause problems.
2. Inspect the Linkage (Automatic): If you're comfortable working on a car, visually inspect the linkage to see if anything is broken, disconnected, or out of adjustment.
3. Professional Diagnosis: The most reliable way to determine the precise cause is to have a qualified mechanic diagnose the problem. They can use specialized tools and their expertise to pinpoint the issue and recommend the best course of action (repair vs. replacement). Ignoring this could lead to further transmission damage.
Ignoring the problem could result in more extensive and expensive damage to the transmission in the long run. Get it checked out sooner rather than later.
