P0736 - Reverse Incorrect Gear Ratio
The transmission control module (TCM) has detected that the reverse gear ratio is not within the expected range, indicating internal slippage or mechanical failure within the transmission. This code is set when the TCM compares input and output shaft speeds and finds a discrepancy during reverse operation, often due to worn clutches, valve body issues, or low fluid pressure.
1. Symptoms You Will Notice
- Vehicle moves slowly or not at all in reverse
- Harsh or delayed engagement when shifting into reverse
- Transmission slipping or revving without movement
- Check Engine Light illuminated
2. Most Common Causes
- Worn or damaged friction discs or bands in the reverse clutch pack
- Hydraulic pressure leak in the reverse circuit (seals, retaining rings)
- Faulty or stuck shift solenoid valve
- Incorrect transmission fluid level or condition (low, contaminated, degraded)
- Defective or erratic input or output speed sensor
- Internal mechanical problem in the reverse gear train (gears, shafts, bearings)
- Faulty transmission control module (TCM) or programming error
3. Step-by-Step Diagnosis
Step 1: Check transmission fluid level and condition; top off or replace if necessary.
Step 2: Scan for additional codes and perform a transmission pressure test.
Step 3: Inspect wiring and connectors to the transmission control module and solenoids.
Step 4: Perform a stall test to isolate reverse clutch or torque converter issues.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
No, driving with P0736 can cause further transmission damage. It is best to have the vehicle towed to a repair shop.
How much does it cost to fix?▼
Costs vary from $150 for a fluid change and solenoid replacement to $400 or more for internal transmission repairs or replacement.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.