Parts
$50-3500+
P0730 — Incorrect Gear Ratio
CAUTIONIs it safe to drive? The transmission is slipping or stuck — the ratio between input and output speed doesn't match the commanded gear. Drive gently; continued driving risks internal damage.
What P0730 means
The TCM compared input vs. output speed and the ratio didn't match any valid gear. This is a catch-all for mechanical slippage — worn clutch packs, solenoid issues, or low fluid — but also triggers when speed sensors are bad. Exact behavior varies by make. Check fluid FIRST.
Most likely causes (in order)
- Low or burnt transmission fluid (top cause — check immediately)
- Worn clutch packs or bands
- Faulty shift solenoid(s)
- Speed sensor fault generating false ratio error
- Internal valve body issue
Symptoms you might notice
- Slipping
- Hunting between gears
- Harsh engagement
- Limp mode
What to check first
Check fluid level and condition immediately — dark, burnt fluid with debris tells you the real story. If fluid is clean, read all trans codes and live data to separate a sensor issue from a mechanical one before opening the transmission.
Repair cost & difficulty
Labor
2-20+ hr
Difficulty
Advanced