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1998 GMC K1500 5.7L 4L60E Transmission P0740 Code: Intermittent Lunge at Stop - Diagnosis and Fixes

Model: 1998 GMC K1500 Fault Code: P0740 Posted: 2010-05-11 20:41

My 1998 GMC K1500 with a 5.7L engine and 4L60E transmission is displaying fault code P074-40. The truck exhibits intermittent lurching behavior when coming to a stop, similar to what you'd see in a manual transmission if the clutch were forgotten. This suggests the torque converter clutch (TCC) may be staying engaged instead of disengaging properly. I've already inspected the external wiring and found no visible issues. To address this, I recently ordered both the TCC solenoid and its associated wiring harness, as well as a PWM TCC solenoid. Is this the correct approach to resolve the P0740 issue? Any additional steps or components worth checking? Thanks for your guidance.

Related fault codes
P0740
Comments (5)
Anonymous 2010-05-12 06:02

Yes, that's a good direction. Don't forget to verify the internal circuit inside the transmission when you have access—sometimes the issue lies in the internal wiring or connections within the transmission itself.

Anonymous 2010-05-23 20:30

I recently replaced both the internal wiring harness and the TCC solenoid, as well as the PWM TCC solenoid. After driving it, I noticed the P0740 code returned when slowing down from about 45 MPH to a stop. I thoroughly checked all external wiring for open circuits or ground shorts—everything appears intact. I also disassembled the Vehicle Control Module (VCM) and inspected for cold solder joints. No issues found. At this point, I'm considering replacing the VCM as my next step. Does that seem like a reasonable next choice?

Anonymous 2010-05-24 15:19

Good point—first, confirm whether the transmission control module (TCM) is actually sending the command to engage the TCC. Have you checked power and ground connections at the solenoid? Are all relevant fuses intact and functioning?

Anonymous 2010-05-24 20:54

The TCM activates the TCC solenoid by applying a ground signal to its circuit. I've confirmed that both power and ground are present, and all related fuses are good. Wiring integrity has been verified throughout the external harness.

Anonymous 2010-05-25 04:49

If the signals from the TCM are correct and wiring is intact, then it's likely one of the solenoid components or the VCM itself is defective—those would be the most probable root causes at this stage.