How to Inspect a Used Car Transmission During a Test Drive

Choosing a used car is an exciting process, but one component you should pay close attention to is the transmission. As a critical part of your vehicle, transmission issues can lead to complex and costly repairs. A thorough inspection during a test drive can save you from future headaches.

Start with the Vehicle History Report

Before hitting the road, review the car’s history. A vehicle history report, like those from CARFAX, reveals the transmission’s past, including mileage and repairs. Frequent repairs or a high mileage of over 150,000 miles may indicate significant wear.

Signs of a Bad Transmission

Here are some red flags to look for:

• Lack of Response: If the gears hesitate to engage or fail to respond, it’s a clear symptom of trouble.
• Strange Noises: Listen for howling, buzzing, or humming sounds—they could signal internal issues.
• Fluid Leaks: Transmission fluid leaks are a telltale sign of potential problems. Don’t be misled by a spotless engine; sellers sometimes clean leaks to mask them.
• Gear Slipping: If gears slip into neutral unexpectedly or don’t stay engaged, it could be dangerous and expensive to fix.
• Burning Smell: A burnt odor from the transmission fluid could indicate overheating and internal damage.

How to Test an Automatic Transmission

Follow these steps during a test drive:

1. Shift Test: With the engine warmed up, move the gear lever through all positions (P, R, D) while holding the brake. There should be no delays, jerks, or unusual noises.
2. Smooth Shifting: Drive the car up to 60 mph, ensuring smooth, jolt-free transitions through all gears. Check for steady RPM levels—no more than 2,000 for a 6-speed or 3,000 for a 4-speed gearbox.
3. Downshift Check: Accelerate, then coast. Gears should downshift seamlessly without noise or jerking.
4. Overdrive Function: If available, test Overdrive. It should shift up one gear when on and downshift when off.

How to Test a Manual Transmission

Manual transmissions are simpler but still require careful evaluation:

• Clutch Test: Press and hold the clutch. A metallic noise might mean the release bearing is worn.
• Silent Neutral: In neutral, the gearbox should remain silent. Noise could indicate low-quality or insufficient oil.
• Gear Shifts: Test all gears, including reverse, for smooth engagement. Accelerate under load to ensure RPM and speed increase evenly.