P0734 on Hyundai: How to Diagnose & Fix
Gear 4 Incorrect Ratio
1 Hyundai model · 1 documented issue · 1 critical · $200-$3,500 repair
P0734 on Hyundai by model: symptoms, diagnosis and fix
The Veracruz uses an Aisin-Warner A6LF1 6-speed automatic transmission that develops harsh shifting and torque converter shudder. The most common complaint is a shudder during light-throttle acceleration at 35-50 mph caused by torque converter clutch material breakdown. The valve body solenoids also develop wear, causing delayed 2-3 and 4-5 upshifts. Hyundai extended the transmission warranty to 10 years/100,000 miles on some affected vehicles through TSB 09-AT-001.
Common Symptoms
- Shudder or vibration at 35-50 mph during light acceleration
- Harsh or jerky 2-3 upshift
- Delayed engagement from Park to Drive
- Transmission slipping under heavy acceleration
- Check engine light with transmission-related codes
How to Fix
A transmission fluid flush with Hyundai SP-IV ATF and a transmission control module (TCM) reflash can resolve early-stage shudder. For persistent shudder, the torque converter must be replaced. Valve body rebuild or replacement is needed for harsh shifting. Check with the dealer for extended warranty coverage under TSB 09-AT-001.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Genuine Hyundai ATF JWS-3309/T-IVOEMHyundai 00232-19023
Confirm VIN, quantity and service-level procedure; this is not SP-IV and cannot r
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Owner tips & cautions
- TipTry a fluid flush with genuine Hyundai SP-IV ATF and a TCM reflash first — this resolves about 60% of shudder cases for under $300
- TipAsk dealer about extended transmission warranty under TSB 09-AT-001 — coverage may be 10 years/100,000 miles for affected VINs
- WarningDo not use generic ATF — the A6LF1 requires Hyundai SP-IV specifically. Wrong fluid accelerates clutch material breakdown.
Sources for this issue (1)
P0734 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0734 mean on a Hyundai?
P0734 stands for "Gear 4 Incorrect Ratio." This code means the Transmission/Powertrain Control Module detected an incorrect gear ratio in 4th gear. The module continuously compares input shaft speed to output shaft speed; if the ratio in 4th gear doesn't match the expected value, it sets P0734. This usually indicates the transmission is slipping or not fully engaging 4th gear due to a hydraulic, friction, or solenoid problem. Symptoms include slipping, flaring RPM, harsh or missed shifts, and possibly limp mode. On Hyundai it is documented across 1 model: Veracruz.
What are the most common causes of P0734?
The most common causes of P0734 are: Low or degraded/burnt transmission fluid, Slipping clutch packs or worn friction elements in 4th gear, Stuck or faulty shift solenoid, Valve body / internal hydraulic leak or restriction, Worn or failing torque converter, Faulty input or output speed sensor, Internal mechanical wear (bands, planetary gears). The specific cause varies by vehicle.
How much does it cost to fix P0734 on a Hyundai?
Published repair estimates on Hyundai range from $200 to $3,500 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for P0734 on a different make?
View P0734 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.