Tech Tip: GM Vehicle has DTC P0757 Set, MIL Illuminated and Slipping Transmission

Tech Tip: GM Vehicle has DTC P0757 Set, MIL Illuminated and Slipping Transmission

Some customers may comment on any of the following conditions - an illuminated MIL (where DTC P0757 is found as a history code), no third and fourth gear and the the transmission does not shift correctly.

Models affected:
– 2007 and prior GM Passenger Cars and Light Duty Trucks;
– 2003-’07 HUMMER H2;
– 2006-’07 HUMMER H3; and
– 2005-’07 Saab 9-7X
with 4L60-E/4L65-E/4L70-E Automatic Transmission (RPOs M30/M32/M70).

Figure 1Some customers may comment on any of the following conditions:
• An illuminated MIL where DTC P0757 is found as a history code in the PCM or TCM;

• No third and fourth gear;

• The transmission does not shift correctly;

• The transmission feels like it shifts to Neutral or a loss of drive occurs; and/or

• The vehicle free wheels above 30 mph. High rpm needed to overcome the free wheeling.
This condition may be caused by any of the following:

• Chips or debris plugging the bleed orifice of the 2-3 shift solenoid (367). This will cause the transmission to stay in second gear when third gear is commanded and return to first gear when fourth gear is commanded.

• A 2-3 shift valve (368) or 2-3 shuttle valve (369) that is stuck, restricted and/or hung-up in its bore.

This condition may also be an indication of a damaged 2-4 band or 3-4 clutches. This clutch damage may generate debris causing the 2-3 shift valve line-up to stick in the valve body bore and set DTC P0757.

1. Inspect the condition of the transmission fluid for signs of overheat or a burnt odor. If either is noted, the transmission should be disassembled for further investigation and repaired as needed.

See Figure 1.

2. Inspect the inside of the oil pan for signs of clutch friction material. A small amount of friction material in the bottom of the pan is normal. If a large amount of clutch material is noted in the fluid or bottom pan, the transmission should be disassembled for further investigation and repaired as needed.

3. Inspect and clean the 2-3 shift valve (368), the 2-3 shuttle valve (369) and the valve bore of debris/ metal chips.

4. Inspect and clean the 2-3 shift solenoid (367B) opening of debris/metal chips. While inspecting the 2-3 shift solenoid (367B), look for a screen over the solenoid opening. If the solenoid does not have a screen, replace the solenoid. All current GMSPO stock shift solenoids have a screen over the solenoid opening.

5. If clutch debris is found, it is also important to inspect the pressure control (PC) solenoid valve fluid screens. Clean or replace the PC solenoid as necessary. It is also important to flush and flow-check the transmission oil cooler using J 45096.

Refer to SI “Automatic Transmission Oil Cooler Flushing and Flow Test” for the procedure.

Refer to the appropriate service manual for additional diagnostic information and service procedures.

Courtesy of Mitchell 1.

You May Also Like

Simplifying AWD Systems

No matter the manufacturer, there is almost always an all-wheel drive (AWD) option for most platforms.

No matter the manufacturer, there is almost always an all-wheel drive (AWD) option for most platforms. Most of these systems are designed to be transparent to the driver.

Many AWD systems came onto the market in the 1990s. Unlike 4x4 truck systems of the day, these systems were always engaged and could not be disengaged by the driver. Many of the early systems used mechanical ways to manage the distribution of power to the four wheels. Most of these systems used viscous differentials and limited slip differentials with special fluids inside. These components were prone to failure and are expensive to manufacture. Also, the performance of these systems could be challenging to control with sensors and actuators. Moreover, these AWD systems could cripple fuel efficiency.

Driveshaft, Axle and Drivetrain Noise FAQs

These are some of the frequently asked questions about driveshaft, axle and drivetrain noise.

Drivetrain: Diagnostic Test Drive

Driveshaft problems can be spotted from the moment you put the vehicle in gear to pull it into a bay.

Constant-Velocity Axle Options

Whether new or remanufactured, complete CV axle assemblies can throw you a curveball from time to time.

Transmission Valve Body Replacement

Learning how to perform drivetrain diagnostics and “in-the-car” repairs is important.

Other Posts

Winter ASE Registration Open

Three options offered for testing and recertification.

Federated 50/50 Challenge Awards Over a Hundred Prizes

Federated conducted the 50/50 Challenge to recognize and thank ASE-certified automotive service professionals.

Mitchell 1, ASE Present 2022 Technician of the Future Award

Nathanial “Nate” Nie of Mission Viejo, California, was named the 2022 Mitchell 1 / National Institute for ASE Technician of the Future.

Schaeffler Group Releases Series of LuK TSBs

In conjunction with its REPXPERT service brand, Schaeffler provides technical tips and service information for LuK products.