Gear 5 Incorrect Ratio

What it means

While fifth gear was commanded, the transmission computer found that the ratio between input and output speed does not match fifth gear. This code applies to transmissions with five or more gears, and drivers usually notice it at high highway speeds.

Related codes: P0730P0734P0784P0765P0868

Symptoms4

• Engine speed rising at high speed without a matching gain in road speed.
• Sudden engine speed flare on the 4-5 shift.
• Transmission staying in fourth or repeatedly dropping out of fifth.
• Check engine light on and higher highway fuel consumption.

Possible causes5

• Low or degraded transmission fluid.
• A faulty solenoid that controls fifth gear.
• A valve body fault or a leak in the fifth gear circuit.
• Worn clutch or band that applies fifth gear, depending on design.
• Damaged internal seals for this clutch.

How to diagnose5

1. Check the fluid level and condition.
2. Watch input and output speed in fifth gear at steady highway cruise.
3. Confirm the difference between engine speed and input speed is normal to rule out torque converter slipping.
4. Read solenoid and shift codes such as P0784, and test the solenoids with a scan tool.
5. Have a hydraulic pressure test done in fifth gear.

How to fix5

1. Correct the fluid level, or change the fluid and filter.
2. Replace the faulty solenoid.
3. Repair or replace the valve body.
4. Repair the clutch or band that applies fifth gear, along with its seals.
5. Clear the codes and confirm steady engine speed in fifth gear on a highway road test.

The cost is low when fluid or a solenoid is the cause, and much higher when the transmission must be opened to repair the internal clutch or band.

Prices are rough estimates for common cars at independent workshops and vary with the car and the source of the part.
Prices last updated: September 2026

Frequently asked questions