Gear 5 Incorrect Ratio
The P0735 code means the vehicle's onboard diagnostic system has detected: Gear 5 Incorrect Ratio. This is a critical severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- hard
- Estimated cost
- $200 - $4000 (parts and labor)
Read and clear transmission codes. Many trans codes are caused by low or burnt fluid -- check level and color before assuming the worst.
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Common Symptoms
- Check Engine Light illuminated
- Slipping in fifth gear
- RPM higher than normal at highway speeds
- Reduced fuel economy
- Transmission may drop to fourth gear
Probable Causes (Ranked by Likelihood)
- Worn fifth gear clutch pack Very High
- Faulty fifth gear shift solenoid High
- Valve body malfunction Moderate
- Low transmission fluid Moderate
Step-by-Step Diagnostic Procedure
-
Monitor fifth gear ratio using input and output speed sensors
-
Check fifth gear solenoid operation with scan tool
-
Perform line pressure test
-
Check transmission fluid level and condition
-
Transmission rebuild likely needed for internal wear
Common Fixes by Vehicle
What techs usually find when diagnosing P0735 on specific vehicles — tap your vehicle for the fix and the exact part:
2005-2017 Toyota Camry/Avalon U250E Easy (fluid), Advanced (solenoid) DIY
5th gear ratio error on the U250E 6-speed typically indicates C1 clutch pack wear or a solenoid issue. Toyota WS ATF should be changed every 60K miles despite the 'lifetime fill' claim. Start with a drain-and-fill, then monitor. If the code returns, the SL1 linear solenoid may be sticking. Solenoid access requires valve body removal from below -- the transmission stays in the vehicle.
Labor: 30 min (fluid), 4-6 hours (solenoid)2007-2018 GM Silverado/Tahoe 6L80E Easy (fluid), Advanced (rebuild) DIY
5th gear on the 6L80E uses the 4-5-6 clutch pack. Ratio errors typically only appear at highway speeds during light-throttle cruising. Check for torque converter shudder first -- a failing converter clutch can mimic gear ratio issues. If the converter is good, the 4-5-6 clutch pack is worn. A transmission fluid change with Dexron VI and a converter drain can extend clutch life temporarily.
Labor: 30 min (fluid), 10-12 hours (rebuild)2010-2020 Ford F-150 6R80 Easy (fluid), Advanced (valve body) DIY
5th gear ratio faults on the 6R80 are less common than lower gear faults and often indicate a valve body issue rather than hard-part failure. Ford IDS can run a clutch performance test to verify. If the valve body is the culprit, a remanufactured valve body (Sonnax updated) is the recommended fix. Always replace the valve body gaskets and solenoid seals during the repair.
Labor: 30 min (fluid), 5-7 hours (valve body)Frequently Asked Questions
Can I drive with code P0735?
Drive short distances only. An incorrect gear ratio indicates the transmission is slipping or not engaging properly. Continued driving can cause catastrophic transmission failure.
Does P0735 mean I need a new transmission?
Not always, but often. If the cause is a worn clutch pack or band, a transmission rebuild or replacement is typically necessary. If a solenoid or valve body is the cause, repair may be less extensive.
How is gear ratio measured for P0735?
The TCM compares input shaft speed to output shaft speed. The calculated ratio should match the expected gear ratio. When the ratio deviates beyond a threshold, the code is set.
Sources
This page is built from documented references. Verify against your own service info before repair work.
P0735 on Diesel, EV & Equipment
The same code ID appears across other engines and platforms. The diagnostic flow varies by manufacturer — these are the platform-specific breakdowns:
See All Codes & Fixes for Your Vehicle
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