4T65E Transmission Valve Body Inspection Procedure - keywords DTC MIL P0756 P0757 performance SES shift slip

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Valve bodies continue to represent a high frequency replacement item on the subject 4T65E transmission. In an effort to reduce the number of no problem found valve bodies returned to the WPC, it is suggested the following occur prior to replacement of the valve body.

Dealer technicians should refer to Dealer Technical Bulletin # 02-07-30-013A. Depending upon customer complaint, refer to the chart listed in the DTB to help identify the circuit within the valve body that may be contributing to the shift concern. Use the valve nomenclature chart to identify the restricted and/or stuck valve when documenting the cause and correction on the repair order. We recommend using both the nomenclature and valve number when documenting the results on the repair order. Use of the DTB will result in improved diagnosis and correction of the shift concern with the least amount of customer inconvenience. Remember, technicians should be instructed to perform a visual inspection of the valve body cavities and perform the following.

1. With valve body removed and on workbench, carefully push valve against spring pressure to check if valve will snap back to original position. Or for the valves seated in home position, use a small flat blade screwdriver and carefully pry the valve off its seat, quickly remove the screwdriver allowing the valve to return to seat. If valve does not snap back unencumbered then the valve will need to be removed from the valve body.
2. Once valve is removed inspect for any scratching or scoring.
3. If any is found then the fingernail test will need to be performed.
4. Using your fingernail to move over scratches to see if nail will try to catch on the scratch or score.
5. If so then valve body will need to be replaced.
6. It has been found that in most cases that the scratches are not severe enough to catch your fingernail.
7. In this case the valve should be cleaned with some type of contact or brake cleaner.
8. The bore should also be cleaned. Clean with machined side down so debris may escape.
9. Blow off with shop air.
10. To verify free movement of the valve, dip into clean ATF and install valve back into the appropriate bore, the valve should move freely. If the valve moves freely, in most cases the valve body will function properly when reinstalled.
11. Reassemble and retest.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.