4T65E TCC Chuggle - kw hesitation hot intermittent misfire miss shudder surge warm

The following diagnosis might be helpful if the vehicle exhibits the symptom described in the PI.

Dealers may comment on a chuggle, surge, misfire condition on 99-01 WB CB and HB cars equipped with the 4T65E at highway speeds.

If this condition is encountered

1. Carefully inspect the main engine wiring harness where it is routed by the A/C accumulator (this may differ between different engines).
2. Commanding the TCC on with the Tech 2 should eliminate the chuggle surge concern.
3. The TCC brake switch should also be inspected to ensure that it is not cycling.
4. If commanding the TCC on with the Tech 2 does not eliminate the concern, then repairs should be focused on the internal leaks.
5. If commanding the TCC on with the Tech 2 does not eliminate the concern and TCC slip speed is 30 RPM or less engine performance issues should be addressed
6. If inspection of the wiring harness or commanding TCC on with Tech 2 and or the TCC brake switch do not reveal the concern then obtain a snapshot during the condition. Graph the TCC duty cycle and look for a saw tooth pattern. TCC duty cycle will range from about 40-80%.
7. If this pattern is observed then the PCS is possibly out of range causing this concern. The following steps should be performed in an effort to correct the TCC chuggle condition.

A. The PCS should be replaced.

B. While the PCS solenoid is removed the Torque Signal Valve (321) should be stroked to ensure that it is not sticking or binding in the bore and the PWM solenoid inspected for being damaged.

C. If the Torque Signal Valve (321) is sticking or bind then perform the following Valve Body Cleaning Procedure.

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 .
12. After the PCS has been replaced and if necessary the Valve Body has been cleaned or replaced in extreme circumstances then both battery cables should be removed overnight to reset the TCC adapts in the PCM. (Touching the battery cables together will not reset the Adapt Values).
13. Install the battery cables and test drive the vehicle to see if the TCC chuggle has been eliminated. Proceed to step 14 ONLY if the condition is still present.
14. If the concern is still present after having the battery cables disconnected overnight the PCM should then be replaced.

The PI number (#) must be included on the TAC case non keyword line, whenever it is recommended to a technician.

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Please follow this diagnosis 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. If these steps do not resolve the condition, please contact GM TAC for further diagnostic assistance.

(99-01 Buick Century) and (99-01 Buick Regal) and (99-01 Chevrolet Monte Carlo) and (99-01 Chevrolet Impala) and (99-01 Oldsmobile Intrigue) and (99-01 Pontiac Grand Prix) and (99-01 Pontiac Bonneville) and (99-01 Buick Park Avenue) and (99-01 Buick Le Sabre) and (99 Oldsmobile Eighty Eight)

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