Drivable short-term, but fix now to avoid damage.
P0730 means the transmission computer noticed the actual gear ratio doesn't match the gear it commanded. In plain terms, the transmission isn't behaving the way it should for the selected gear, often due to slipping or internal wear. This is a serious code that usually needs prompt attention.
$200 – $3500
Varies by vehicle and root cause.
It's not recommended. P0730 often signals slipping or internal trouble, and driving on it can turn a moderate repair into a full transmission rebuild. If it's slipping, get it towed.
A fluid service or solenoid fix might be $200-$600, but if internal clutches are worn, a rebuild or replacement can reach $2,000-$3,500 or more.
Yes, it's a high-severity code. It points to the transmission not delivering the correct gear ratio, which can mean internal wear and rapidly worsening damage if ignored.
Not always, but it can. Sometimes it's just low fluid or a solenoid, but it can also indicate worn internal parts, so a proper diagnosis is important before assuming the worst.