How Can I Tell If My Automatic Transmission Needs An Overhaul?

How Can I Tell If It's Just A Solenoid Failure?

The electronically controlled 42RE, 44RE, and 46RE automatic transmissions have several solenoids and sensors that the PCM (or Transmission Control Module = TCM) needs to control the upshifts and downshifts. If any one of these sensors/solenoids fail or the fuse(s) that supplies the solenoids gets blown, the transmission will go into ‘Limp In Mode’.

What makes it pretty easy to tell if the automatic transmission failure is just a solenoid related issue is the fact that, in 99.9% of the cases, the transmission doesn't ‘slip’.

Here are some very specific symptoms you'll see when a transmission solenoid goes bad:

1. The PCM is also gonna' light up the check engine light (CEL) and store a specific shift solenoid diagnostic trouble code (DTC). All generic OBD II transmission diagnostic troubles codes start with: P07XX (the XX being the last 2 digits of the DTC).
2. You'll see one or several of the following transmission diagnostic trouble codes:
   • P0700: Transmission Control System Malfunction.
   • P0711: Transmission Fluid Temperature Sensor Circuit Range/Performance.
   • P0712: Transmission Fluid Temperature Sensor Circuit Low Input.
   • P0713: Transmission Fluid Temperature Sensor Circuit High Input.
   • P0720: Output Speed Sensor Circuit Malfunction.
   • P0740: Torque Converter Clutch Circuit Malfunction.
   • P0743: Torque Converter Clutch Circuit Electrical.
   • P0748: Pressure Control Solenoid Electrical
   • P0753: Shift Solenoid A Electrical.
   • P0783: 3-4 Shift Malfunction.
3. You may see one, or several, of the following Manufacturer Specific DTCs:
   • P1756: Governor Pressure Not Equal To Target At 15-20 PSI.
   • P1757: Governor Pressure Above 3 PSI When Request Is 0 PSI.
   • P1762: Governor Pressure Sensor Offset Improper Voltage.
   • P1763: Governor Pressure Sensor Voltage Too High.
   • P1764: Governor Pressure Sensor Voltage Too Low.
   • P1765: Trans 12 Volt Supply Relay Control Circuit.
4. The speedometer does not work and you might have one of the following trouble codes:
   • P0500: Vehicle Speed Sensor Malfunction.
   • P0501: Vehicle Speed Sensor Range/Performance.
   • P0502: Vehicle Speed Sensor Low Input.
   • P0503: Vehicle Speed Sensor Intermittent/Erratic/High.
5. Your 42RE, 44RE, or 46RE automatic transmission will stay in ‘Limp In Mode’, which means it'll stay in 2nd gear no matter what the vehicle speed.
6. As you accelerate your vehicle, it feels very underpowered. This is due to the fact that the transmission is starting out in 2nd gear.
7. At speeds over 35 MPH, the engine feels like it's over-revving. This is also due to the fact that the transmission is staying in 2nd gear and the gear ratio provided by 2nd gear is gonna' keep the engine working pretty hard at any speed above 35 MPH.

Remember, what will tell you that you have a solenoid or internal transmission sensor problem is:

1. You'll have a specific transmission diagnostic trouble code (or a speed sensor diagnostic trouble code).
2. The automatic transmission does not ‘slip’, no matter how many times you road test your vehicle.
3. The 42RE, 44RE, or 46RE stays in ‘Limp In Mode’.

Let's move on to the next subheading and find out more about the specific symptoms a 42RE, 44RE, or 46RE with internal damage.

How Can I Tell If It's Internal Transmission Damage Requiring An Overhaul?

The biggest give-away, that your vehicle's automatic transmission is kaput and in need of an overhaul or replacement is that it will ‘slip’.

Here are some more specifics that will let you know if it's time for an overhaul or replacement:

1. The transmission fluid level is OK, but it's very dark to black and has a ‘burned out’ smell.
2. Usually (but not always), the PCM will set a ‘gear ratio error’ transmission diagnostic trouble code. Here are some more specifics:
   • P0730: Incorrect Gear Ratio.
   • P0731: Gear 1 Incorrect ratio.
   • P0732: Gear 2 Incorrect ratio.
   • P0733: Gear 3 Incorrect ratio.
   • P0734: Gear 4 Incorrect ratio.
   A gear ratio error trouble code is the PCM's way of letting you know that it knows the transmission is ‘slipping’.
3. As you accelerate your vehicle, the transmission feels like it was thrown into neutral all of a sudden.
4. No 1st gear. Specifically, you put the transmission in drive but no matter how much you accelerate the engine, your vehicle does not move.
5. The transmission shifts into 1st gear a few seconds after you've come to a complete stop causing a very noticeable jolt (this jolt is more pronounced the faster you've been traveling and the quicker you come to a complete stop). The normal behavior is the transmission shifting into 1st gear before you come to a complete stop.
6. No Reverse gear, although the transmission seems to work fine in Drive.
7. When you remove the transmission oil pan, you find dark sediment. This sediment is the friction material that has fallen off the friction discs (which are located inside the transmission).
8. You may find metal shavings in the fluid pan mixed in with the friction material sediment on the transmission's oil pan.

Removing the transmission oil pan to see if you have metal shavings and/or friction material sediment on the pan is what will give you the definite proof that you have internal transmission damage (and in need of a transmission overhaul).