P0735 on Infiniti: How to Diagnose & Fix
Gear 5 Incorrect Ratio
1 Infiniti model · 1 documented issue
On Infiniti vehicles, P0735 (gear 5 incorrect ratio) is most often reported on the 2009-2013 Infiniti G37 as 7-Speed Automatic (RE7R01A) Harsh 2-1 Downshift, Gear Hunting and Ratio DTCs Requiring TCM/ECM Reflash ($0-$250 repair). Have an Infiniti dealer apply the latest TCM/ECM reprogram (bulletin family ITB10-075 / ITB12-027 and later revisions) with CONSULT-III; many owners report the harsh 2-1 downshift and hunting are cured or greatly reduced. If ratio codes persist after the reflash, the dealer flow is to inspect fluid level/condition and replace the valve body or torque converter. Each section below gives the symptoms, how to confirm the cause, the fix, parts and sources for that model.
Common causes of P0735 (all vehicles)
- Low or degraded/burnt transmission fluid
- Slipping clutch packs or worn friction elements in 5th 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 inside the transmission
P0735 on Infiniti by model: symptoms, diagnosis and fix
The 7-speed automatic introduced for the 2009 G37 developed a widely reported drivability complaint: a hard clunk on the 2nd-to-1st downshift when coasting to a stop, gear hunting/searching under light throttle, delayed or harsh upshifts when cold, and in some cases stored incorrect-gear-ratio codes. The MyG37 '7-speed transmission reprogram' thread runs well past 170 pages of owner reports. Infiniti responded with a series of TCM/ECM reprogramming bulletins (owners cite ITB10-075 and later ITB12-027 revisions) rather than hardware replacement; only a minority of cars needed a torque converter or valve body.
Common Symptoms
- Hard clunk or jerk on the 2-1 downshift when stopping
- Transmission hunts between gears at light throttle
- Delayed or harsh shifts when cold
- Check engine light with gear-ratio codes
How to Fix
Have an Infiniti dealer apply the latest TCM/ECM reprogram (bulletin family ITB10-075 / ITB12-027 and later revisions) with CONSULT-III; many owners report the harsh 2-1 downshift and hunting are cured or greatly reduced. If ratio codes persist after the reflash, the dealer flow is to inspect fluid level/condition and replace the valve body or torque converter. No recall; reflash was covered under powertrain warranty and is a nominal-cost labor item out of warranty.
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View P0735 across all makes →Frequently asked questions
What does P0735 mean on a Infiniti?
P0735 stands for "Gear 5 Incorrect Ratio." This code means the Transmission/Powertrain Control Module detected an incorrect gear ratio in 5th gear. By comparing input shaft speed to output shaft speed, the module verifies each commanded gear; when the 5th-gear ratio is wrong, P0735 is stored. This typically means the transmission is slipping or failing to lock into 5th gear due to fluid, friction, or solenoid issues. Drivers may notice slipping at highway speeds, RPM flare, poor fuel economy, or limp mode. On Infiniti it is documented across 1 model: G37.
How do I diagnose P0735 on a Infiniti G37?
Have an Infiniti dealer apply the latest TCM/ECM reprogram (bulletin family ITB10-075 / ITB12-027 and later revisions) with CONSULT-III; many owners report the harsh 2-1 downshift and hunting are cured or greatly reduced. If ratio codes persist after the reflash, the dealer flow is to inspect fluid level/condition and replace the valve body or torque converter. No recall; reflash was covered under powertrain warranty and is a nominal-cost labor item out of warranty. Published repair guidance and available estimates are in the G37 section on this page.
What causes P0735 on Infiniti vehicles?
Documented causes on Infiniti: 7-Speed Automatic (RE7R01A) Harsh 2-1 Downshift, Gear Hunting and Ratio DTCs Requiring TCM/ECM Reflash. Generic causes of P0735: Low or degraded/burnt transmission fluid, Slipping clutch packs or worn friction elements in 5th gear, Stuck or faulty shift solenoid, Valve body / internal hydraulic leak or restriction.
How much does it cost to fix P0735 on a Infiniti?
Repair costs vary widely with the root cause and Infiniti model; each issue on this page carries its own estimate where one is published.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.