P0731 on Chevrolet
Gear 1 Incorrect Ratio
P0731 on Chevrolet vehicles indicates gear 1 incorrect ratio. Au7o has documented this code across 2 Chevrolet models — most commonly on Cruze, Silverado 1500. This code means the Transmission/Powertrain Control Module detected an incorrect gear ratio in 1st gear. The module compares input (engine/turbine) speed to output shaft speed; when the car is commanded into 1st but the calculated ratio doesn't match the expected value, P0731 sets. This points to slipping, an incorrect shift, or a hydraulic/mechanical problem rather than just an electrical fault. You may feel slipping, harsh or delayed engagement, or the transmission may go into a limited 'limp' mode. Typical repair costs on Chevrolet range from $1,500 to $4,000, depending on the specific model and root cause.
Common Causes of P0731
- •Low or degraded/burnt transmission fluid
- •Slipping clutch packs or worn friction components
- •Stuck or faulty shift solenoid affecting 1st gear
- •Internal hydraulic leak / valve body fault
- •Worn or failing torque converter
- •Faulty input or output speed sensor
- •Mechanical wear (planetary gears, bands) inside the transmission
P0731 on Chevrolet by Model
Chevrolet Cruze(1 issue)
- 6T40 3-5-Reverse Wave Plate Fracture - Sudden Loss of 3rd, 5th and Reverse2011-2013
The early (Gen 1) 6T40/6T30 automatic uses a stamped steel wave plate in the 3-5-Reverse clutch pack. On 2011-2012 builds the plate cracks and shatters without warning, instantly wiping out 3rd gear, 5th gear and reverse. The car will usually still move in 1st, 2nd, 4th and 6th, so drivers often describe it as 'it flared, then it won't back up.' Debris from the shattered plate circulates through the valve body and contaminates the whole unit. This is distinct from the well-known torque-converter shudder - it is a hard mechanical failure, not a driveability complaint. GM revised the wave plate in later 6T40 builds and the failure rate drops sharply on 2013+ cars.
Chevrolet Silverado 1500(1 issue)
- 4L60E Automatic Transmission 3-4 Clutch Pack and Sun Shell Failure (Slipping, Loss of 3rd/4th Gear)1994-2010
The 4L60E 4-speed automatic behind the half-ton Silverado is notorious for wearing out its 3-4 clutch pack and cracking the input 'sun shell' (reaction sun gear shell) as mileage climbs. Owners report the truck suddenly loses 3rd and 4th gear (revs up but won't pull) while reverse and low gears still work, or a hard grinding/no-move with a fractured sun shell. The 3-4 clutch is the known weak point and often burns up first; the larger input drum on 2004-and-up units also likes to crack internally. This is one of the single most-searched failures for these trucks.
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View P0731 across all makes →Frequently Asked Questions
What does P0731 mean on Chevrolet?▼
P0731 stands for "Gear 1 Incorrect Ratio." This code means the Transmission/Powertrain Control Module detected an incorrect gear ratio in 1st gear. The module compares input (engine/turbine) speed to output shaft speed; when the car is commanded into 1st but the calculated ratio doesn't match the expected value, P0731 sets. This points to slipping, an incorrect shift, or a hydraulic/mechanical problem rather than just an electrical fault. You may feel slipping, harsh or delayed engagement, or the transmission may go into a limited 'limp' mode. On Chevrolet specifically, this code is documented across 2 models.
What causes P0731 on Chevrolet vehicles?▼
Common causes on Chevrolet: Low or degraded/burnt transmission fluid, Slipping clutch packs or worn friction components, Stuck or faulty shift solenoid affecting 1st gear, Internal hydraulic leak / valve body fault, Worn or failing torque converter. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0731 on a Chevrolet?▼
Repair costs on Chevrolet range from $1,500 to $4,000, depending on the specific model and root cause.
Which Chevrolet models have P0731 documented?▼
Au7o has documented P0731 on 2 Chevrolet models: Cruze, Silverado 1500.