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P0744 often shows up as a shudder around 40–55 mph. The TCC is engaging and disengaging rapidly. A simple ATF flush with the right friction-modifier additive sometimes clears the shudder. If not, electrical or mechanical fault inside the trans is the cause. ATF on Amazon ↑
🗺️ Where Is the Problem?
Blueprint view - P0744 fault localized to the transmission control system / solenoid body
These are statistical causes across ALL vehicles - your exact car may rank differently
For example, on a Honda 4-cyl the downstream O2 sensor causes P0744 64% of the time, but on a GM 5.3L V8 the catalytic converter is the cause 71% of the time. Get a probability ranking built specifically for your year, make, model, and mileage.
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🎯 Top Causes & Probability
50%
#1 - Most Likely
Worn TCC Friction Material
The torque converter's lock-up clutch friction material is worn, glazed, or contaminated. Causes the classic 45 mph shudder. ATF flush with friction modifier sometimes helps; severe cases need a torque converter replacement.
🔩 Part
$200–$700
👨🔧 Labor
$800–$1,800
⚡ DIY Difficulty
Hard
30%
#2 - Check First
Intermittent Wiring/Connector
A wiggle in the trans connector or chafed harness causes the TCC to drop out unpredictably. Cheap fix if found - clean the connector and re-secure the harness.
🔩 Part
$15–$80
👨🔧 Labor
$100–$280
⚡ DIY Difficulty
Medium
20%
#3 - Less Common
Failing TCC Solenoid
The TCC solenoid is on its way out - resistance is in spec at rest but drifts under heat. Replacement requires pan drop.
🔩 Part
$30–$150
👨🔧 Labor
$300–$650
⚡ DIY Difficulty
Hard
🚗 Most Affected Vehicles
🔧 Step-by-Step Diagnosis
- Try a fluid flush with friction modifier - Honda especially: a fluid change with the correct ATF often clears mild TCC shudder for thousands of miles. Wrong fluid spec will make it worse instantly.
- Watch for shudder at exactly 40–55 mph - Light throttle at lock-up engagement is when TCC issues appear. Shudder there confirms TCC; smooth there points to other causes.
📍 Find a Trusted Shop Near You
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Tips for Choosing a Shop
- Ask if they charge a diagnostic fee and whether it applies toward the repair
- Request a written estimate before approving any work
- Ask specifically about the part brand - OEM vs. aftermarket matters for this code
- Check Google reviews for recent mentions of the specific repair you need