Restore Your Envoy’s Shifting Performance
If you’re dealing with the frustrating and often unpredictable behavior of a failing transmission control module in your 2005 GMC Envoy, you’ve come to the right place. As a technician with over two decades of experience, I’ve seen firsthand how a faulty TCM can turn a reliable vehicle into a source of constant stress. Symptoms like harsh, delayed shifts, getting stuck in one gear (limp mode), or an illuminated Check Engine Light can point directly to this critical component. This isn’t just an inconvenience; it’s a matter of drivability and safety.
We offer a dependable and straightforward solution: a replacement Transmission Control Module, part number YKTB, that arrives at your door fully programmed and ready for installation. We take your vehicle’s VIN and flash the module with the latest, most stable software updates from GM. This critical step ensures the TCM communicates flawlessly with your Envoy’s engine and other systems, restoring the smooth, precise shifting you expect. You get a solution that bypasses the expensive and time-consuming trip to a dealership for programming.
From the Diagnostic Bay: The Intermittent Shifting Nightmare
I once had a 2005 Trailblazer EXT (which shares its platform with the Envoy) come into the shop with a problem that was driving the owner crazy. The truck would shift perfectly for days, then suddenly start slamming into gear or refuse to shift out of second. Other shops had replaced solenoids and fluid, but the problem persisted. After hooking up my diagnostic scanner and monitoring live data during a test drive, I saw the TCM was intermittently dropping communication (a classic sign of internal failure). We installed one of our pre-programmed modules, and the problem was solved for good. It’s often the electronic brain, not the mechanical parts, that’s the hidden culprit.
Is Your Vehicle Showing These Symptoms?
- ✔ Erratic or harsh shifting between gears.
- ✔ The transmission seems to slip or hesitate during acceleration.
- ✔ Your vehicle is stuck in a single gear (often called “limp mode”).
- ✔ The Check Engine Light is on with transmission-related codes like P0700, P0751, or U0100.
- ✔ Delayed engagement when shifting from Park to Drive or Reverse.
- ✔ Poor fuel economy due to inefficient shifting.
A Straightforward Guide to Installation
For the 2005 GMC Envoy with the 8-cylinder engine, the TCM is located in the engine compartment on the driver’s side. This is a direct-fit replacement that a confident DIYer or any professional mechanic can perform.
- Safety First: Disconnect the negative terminal from your vehicle’s battery and secure it away from the post to prevent accidental reconnection.
- Locate the Module: Open the hood and find the TCM on the driver’s side (LH) of the engine compartment. It’s often near the fuse box or firewall.
- Disconnect Electrical Connectors: Carefully unclip and remove the electrical wiring harnesses connected to the old TCM. Inspect the connectors for any corrosion or damage.
- Remove the Old Module: Unbolt the mounting hardware that secures the TCM to its bracket. Keep the hardware as you will reuse it.
- Install the New Module: Mount your new, pre-programmed TCM using the original hardware. Ensure it is seated securely.
- Reconnect Everything: Firmly plug the electrical connectors into the new module. You should hear a click as they lock into place. Reconnect the negative battery terminal.
- Final Check: Start the vehicle and allow it to idle for a few minutes. Test drive to confirm that shifting is smooth and the check engine light is off. No further programming is required.
Will This Fit My Vehicle?
This module is a direct replacement for service number YKTB and is also compatible with part numbers 24223112, 24226863, 24233595, 24234189, 24239427, YBWW, YDFC, YDFD, YDLT, YJHY, and YKTF. It is confirmed to fit the following vehicles:
- 2005 Allure: (lower air cleaner housing)
- 2005 Cobalt: (behind LH strut tower)
- 2005 Corvette: (LH frame rail)
- 2005 Envoy: (LH engine compartment), (8 cylinder)
- 2005 Envoy XL: (LH engine compartment), (8 cylinder)
- 2005 Envoy XUV: (LH engine compartment), (8 cylinder)
- 2005 GTO
- 2005 Grand Prix: (lower air cleaner housing)
- 2005 Ion: (behind LH strut tower)
- 2005 LaCrosse: (3.6L), (lower air cleaner housing)
- 2005 Pursuit: (behind LH strut tower)
- 2005 Rainier
- 2004-2005 Rendezvous: (3.6L), (air cleaner box)
- 2005 Trailblazer EXT: (LH engine compartment), (8 cylinder)
Frequently Asked Questions
Do I need to do any programming after I receive this 2005 Envoy TCM?
No. This is the primary benefit of our service. We program the module to your specific vehicle using the VIN you provide during checkout. It arrives ready to install, saving you a trip to the dealership.
What information do you need from me?
After you place your order, you will need to provide us with your vehicle’s 17-digit Vehicle Identification Number (VIN). This is essential for us to load the correct GM software for your Envoy’s specific configuration.
Where is the TCM located on my 2005 GMC Envoy?
For the 2005 Envoy with an 8-cylinder engine, the Transmission Control Module is typically found in the engine compartment, on the driver’s side (LH), often mounted near the firewall or main fuse block.
Will this fix a P0700 trouble code?
A P0700 code is a general fault request from the TCM to the main computer to turn on the check engine light. While a failing TCM is a very common cause, this code can also be triggered by other transmission issues. Replacing a known-bad TCM is the correct step to resolving the root cause of the P0700.
Is this a new or used part?
This is a high-quality, inspected, and tested replacement part that has been verified to meet or exceed original equipment performance. We back it with a warranty to ensure your peace of mind.