P0729Transmission

Gear 6 Incorrect Ratio

P0729 means the transmission is not achieving the correct ratio in sixth gear. The input and output speed sensors show a ratio that does not match the commanded gear, usually from worn clutches, low fluid, or a solenoid fault.

🚗 Limited. An incorrect ratio in sixth gear means the transmission is slipping or not engaging, which causes further damage the longer you drive.

HIGH

severity

🎯 Top Causes, Ranked by Likelihood

#1Low or degraded transmission fluid$100-$300

30%

Low or burnt fluid causes slipping; check first.

#2Worn clutches or bands$1500-$3500

30%

Internal wear prevents sixth gear from holding ratio.

#3Faulty shift solenoid or valve body$150-$900

25%

A stuck solenoid or worn valve body misapplies the gear.

#4Speed sensor fault$100-$350

15%

A bad sensor reports a false ratio.

🩺 Common Symptoms

Slipping in sixth gear
Harsh or delayed shifts
Check engine light
Possible limp mode
RPM flare on acceleration

💰 Repair Cost: DIY vs Shop

DIY Cost

$100-$900

Shop Cost

$200-$3500

📋 Free OBD2 Code Cheat Sheet

The 50 most common codes with likely cause and DIY fix cost. Sent once, no spam.

🔧 How to Diagnose P0729

1Check fluid level and condition first

2Scan for speed sensor and other transmission codes

3Command gears with a scan tool and watch ratios

4Inspect the valve body and solenoids or service the fluid

❓ Frequently Asked Questions

Can I drive with P0729?

Only briefly. Slipping gears create heat and further damage. Diagnose it quickly and check fluid first.

How much to fix P0729?

A fluid service or solenoid is $200-$900. Internal clutch wear can mean a rebuild at $1500-$3500.

Can low fluid cause P0729?

Yes. Low or burnt fluid is a common and inexpensive cause, so verify that before major repairs.

🔗 Related Codes

P0731P0732P0733P0734P0735