Transmission code
P0740: Torque converter clutch circuit problem
How this range is built
| Part of the job | Low | High |
|---|---|---|
| Parts | $60 | $400 |
| Labor: 2 to 5 hours × $125 to $175 an hour | $250 | $875 |
| Fees: shop supplies, disposal, diagnostics | $15 | $40 |
| Total, rounded | $320 | $1,325 |
The hourly rate is the BLS Occupational Employment and Wage Statistics, May 2025 average pay for this trade in Boston, $31.54 an hour, times 4 to 5.5 to cover what a shop bills (overhead, tools, insurance, profit). Parts are a band from budget aftermarket to the manufacturer part. Full method.
Not a repair shop, estimates only. Typical range, estimate. Not a quote. Your car, parts and shop change the number.
This is the range for the most common fix, transmission solenoid replacement. Which repair your car needs depends on a proper diagnosis.
At cruising speed the computer locks the torque converter clutch so the engine and transmission turn as one, which saves fuel. It found an electrical fault in the circuit that controls this lock-up, so the clutch may not engage or may engage at the wrong time.
- Safe to drive?
- Short trips only
- Most common cause
- Failed lock-up solenoid
Mild cases only cost fuel economy. If you feel shuddering or the transmission overheats, stop driving it, since heat harms the unit.
What you may notice
- Shudder at highway speed
- Engine revs high at cruise
- Lower fuel economy
- Harsh shifting
Common causes, most likely first
- Failed lock-up solenoid
- Wiring or connector fault
- Dirty or worn transmission fluid
- Failing torque converter
Check this first
Ask the shop to check fluid level and condition first, then the solenoid circuit, before talking about a converter.
Other repairs that sometimes fix P0740
| Repair | Typical range, Boston |
|---|---|
| Torque converter replacement | $970 to $2,725 |
| Transmission fluid service | $150 to $520 |
| Diagnostic scan (check engine light) | $60 to $290 |
Before you pay
- Ask the shop what test showed this part is the cause, not just that the code appeared.
- Ask for parts and labor listed separately, and for the hours.
- Ask for a written OK before any extra work. Massachusetts rules require written authorization before repairs.
Got a quote already? Check it against the range. Want to see if your car has a recall tied to this problem? Check recalls by VIN.
Need to read a code yourself? OBD-II scanners on eBay (affiliate link, disclosure).
P0740 questions
Will a fluid service fix it?
Sometimes, if the fluid is old and causing the problem, but not if the electrical circuit or solenoid has failed. A shop should check the circuit first so you do not pay for a service that cannot fix it.
Is the torque converter the problem?
It can be, but it is usually checked after the solenoid and fluid. A converter replacement is a large job, so ask the shop to explain what tests point there before agreeing.
Why is my RPM high on the highway?
Without the lock-up, the engine spins faster than it needs to at cruise. Revs sit higher than normal on the highway, and fuel economy drops, even though the car still drives.
How much does it cost to fix P0740?
The most common fix, transmission solenoid replacement, has a typical range of $320 to $1,325 in Boston. It is an estimate built from parts prices and local labor wages, not a quote. Your car and shop change it.
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Code meaning written in our own words. Some codes mean different things on different makes, so check your scan tool or manual. Not a repair shop, estimates only.