Document ID# 1998652 2008 Chevrolet Corvette
Subject: Current DTC P0751 - keywords MIL SES shift slip #PIP4131C - (07/17/2007)
Models: 2007-2008 Cadillac Escalade, Escalade ESV, Escalade EXT, SRX, STS, STS-V, XLR, XLR-V
2007-2008 Chevrolet Corvette, Silverado Equipped With 6L50, 6L80 or 6L90 (RPOs MYB, MYC, MYD) Automatic Transmission
This PI was superseded to update Recommendation/Instructions. Please discard PIP4131B.
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
In an attempt to further understand causes of DTC P0751 an engineering investigation is being conducted.
Recommendation/Instructions:
If a vehicle comes to your dealership with a DTC P0751 as an ACTIVE code in the TCM and the following qualifications are met please call TAC at the number you have been provided.
Vehicle built January 1, 2007 or newer. Use GMVIS to verify vehicle build date.
• DTC P0751 CAN BE duplicated, usually easier to duplicate when the transmission fluid is at operating temperature.
• Note the freeze frame / fail records or use the Tech 2 to record the freeze frame / fail records. This information will be provided to TAC.
If the vehicle was built prior to January 1, 2007
• Check and note the transmission fluid level and condition.
• If the level is high or low it should be corrected and the vehicle road tested to verify that the condition is still present.
• Remove the transmission bottom pan to inspect for possible debris.
• If debris is found the transmission should be disassembled to determine the source. Repair or replace the transmission in the most economical method following guidelines in bulletin 02-07-30-029.
• If no debris is noted in the oil pan remove the valve body / control solenoid and module assembly. Disassemble the valve body to:
- Inspect the check balls for roundness ensuring that there are no flat spots
- Inspect the spacer plate for debris, burrs or flashing on the orifices
- Measure all the valve body bore plug (328) for diameter. Specification = 11.502 mm +/- 0.004 mm.
- Undersize bore plugs should be replaced.
- Inspect Clutch select valve 2 (352) (farther from the manual valve) in the lower valve body (307) for freedom of movement and correct travel.
- If a concern is found in the respective valve line-up remove the valve from the valve body.
- Once valve is removed inspect for any scratching or scoring.
- If any is found then the fingernail test will need to be performed.
- Using your fingernail to move over scratches to see if nail will try to catch on the scratch or score.
- If so then valve body will need to be replaced.
- It has been found that in most cases that the scratches are not severe enough to catch your fingernail.
- In this case the valve should be cleaned with some type of contact or brake cleaner.
- The bore should also be cleaned. Clean with machined side down so debris may escape.
- Blow off with shop air.
- To verify free movement of the valve, dip into clean ATF and install valve back into the bore, the valve should move freely. If the valve moves freely, in most cases the valve body will function properly when reinstalled.
- Reassemble and retest.
• If no issues are noted in the valve body inspection replace the control solenoid and module assembly (314).
