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Billy, Chevrolet tecnician
Category: Chevy
Satisfied Customers: 511
Experience:  Over 25 years experience,GM grand master for 8 years,certified smog and government safety inspector
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2003 Tahoe 5.3. Changed trans fluid and filter, kncked off

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2003 Tahoe 5.3. Changed trans fluid and filter, kncked off some kind of sensor/module in front side of valve body. Black plastic with wires attached, covered copper spool type thing. Snapped it back on. Now truck bogs off the line, check engine light on, won't downshift unless you do it manually. Runs fine at road speed. No previous probs, highly maintained.
Hello escapefromNY and welcome to just answer.

The component that got damaged is a shift solenoid, pressure solenoid or tcc solenoid.
the good news is you can fix it at home but and if you can id for me the one that you broke i should be able to help you with some information.

the front side/engine side of the transmission is on the left side of this image.
Object Number: 181573  Size: SH

  1. Disconnect the internal wiring harness electrical connectors from the following components:
  2. The transmission fluid pressure manual valve position switch (1)
    The 1-2 shift solenoid (2)
    The 2-3 shift solenoid (3)
    The pressure control solenoid (4)
    The TCC PWM solenoid (5)
    The 3-2 shift solenoid (6)

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    Best regards,

Customer: replied 8 years ago.


I believe the right side of the diagram is the engine side. The black plastic cap with the attached wires that came off was either #2 or #3, whichever is towards the passenger side of the vehicle. I snapped it back on. Could I have damaged another, like #5, as that is where the pan was binding.The vehicle will not go into overdrive, and will not kick down using the accellerator. From a dead stop it feels like the emergency brake is on. The OBD reading is "Transmission Module". Thanks a million.



hello Sal

Just to make sure # XXXXX 2 and 3 components on the picture are towards the back of the transmission where the rear drive shaft is.
And #5 and 6 towards the front. facing the engine.This is a fact.
If you would be kind enough to take an other look and tell me which one did you brake.
It is really common for people to brake the shift solenoid in the back due to clearance issues with the cross member.

Best regards,
Customer: replied 8 years ago.


I believe it was the shift solonoid, as I did have trouble with pan clearance, and when manipulating it, I felt the truck "jump" like the emergency brake was released. Sound right to you? Any tips on a part number, or removal/installation would be much appreciated. BTW this is a 2wd if it makes a difference. Thanks.



Hello Sal.

If you feel my answer was helpful, please click the ACCEPT button. Feedback & Bonuses are always welcome.

If the component that you "snapped back" in to place was at the back of the transmission
(#2 or #3 on the image i have sent you earlier) than it is a shift valve or valves that got damaged.
The good news is you can easily replace it. Disconnect the battery
Remove the pan again.

Disconnect the electrical connector from the shift solenoid by slightly pulling/bending on the retainer/lever away from the connector. (try not to break this, it could be brittle from the heat)

Remove the small horseshoe clip that holds the solenoid in place. it is located just front of the solenoid and you will have to use a small hook to pull it down and out.

Remove the solenoid by pulling it out backwards toward to back of the transmission.

Remember the one that you broke will have the "nose" piece stuck inside and may not come out with the solenoid, use a small pick to pull it out or to push it out from the bottom.

You will know it is all clear when you can move/feel the shift valve (366 or 369) with your finger in the hole against its spring tension.

I would suggest to replaced both shift valves at the same time, they are not very expensive, they are the same part number and we don't know which one you damaged.
Possibly both.

Lube the seals/orings on the new solenoids with vaseline or transmission fluid.
push into place and retain with the clip.

Object Number: 405074  Size: SH

  1. Install the following items:
  2. 8.1. The 2-3 shift valve (368)
    8.2. The 2-3 shuttle valve (369)
    8.3. The 2-3 shift solenoid valve (367B)
    8.4. The solenoid retainer (395)
Object Number: 405071  Size: SH

  1. Install the following items:
  2. 9.1. The 1-2 shift valve spring (365)
    9.2. The 1-2 shift valve (366)
    9.3. The 1-2 shift solenoid valve (367A)
    9.4. The solenoid valve retainer (395)
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