P0731 Code: Gear 1 Incorrect Ratio
🟠 Moderate severity · drivable
Drivable, but first gear is slipping, which can cause serious internal damage if ignored. Get it checked promptly.
What P0731 means
The transmission is slipping in first gear — the computer commanded first gear, but the actual gear ratio didn't match. A slip limited to first gear points to the clutch pack or band that engages first gear, or to low/old transmission fluid. If several gears slip, the problem is more likely systemic (see P0730).
Symptoms
- Check engine light on
- Slipping when pulling away from a stop
- Harsh or delayed 1-2 shift
- Reduced acceleration from standstill
Common causes
- most common: Low or dirty transmission fluid
- common: Worn first-gear clutch pack or band
- less common: Faulty shift solenoid or valve body
How to fix it
| Fix | DIY? | Typical cost |
|---|---|---|
| Check and change the transmission fluid and filter | Yes | $100–250 |
| Repair internal transmission slippage | Mechanic | $1500–4000 |
Frequently asked questions
Is a first-gear slip serious?
Yes. A slipping first gear usually means a worn clutch pack or band, and continued driving accelerates the damage and can strand you.
What if only first gear slips?
Slipping in just one gear points to that gear's clutch or band. If multiple gears slip, it's more likely a fluid or system-wide problem (P0730).
How much does it cost to fix P0731?
A fluid change is $100–250; an internal rebuild runs $1,500–4,000.
Related codes
P0730
P0730 Code: Incorrect Gear Ratio
P0732P0732 Code: Gear 2 Incorrect Ratio
P0700P0700 Code: Transmission Control System Malfunction
Related guide: The 10 Most Common Check Engine Codes →
Updated 2026-08. This page is informational and not a substitute for professional diagnosis.