If you’re experiencing frustrating and unpredictable transmission behavior in your GMC Yukon XL 1500, the Transmission Control Module (TCM) is often the culprit. As a technician with over two decades of experience, I’ve seen countless GM vehicles sidelined by faulty TCMs. This T42 Transmission Control Module, part number 24243921, is the definitive solution to restore the crisp, reliable shifting your vehicle had when it was new. It arrives at your door fully programmed to your vehicle’s specific VIN, eliminating the need for expensive dealership visits and complex programming procedures. Get your SUV back to performing its best with a dependable, direct-fit replacement.
Is Your Yukon Exhibiting These Transmission Issues?
A failing TCM can manifest in various ways, often starting as a minor annoyance before becoming a major problem. From my experience in the shop, these are the tell-tale signs that your module needs attention. A faulty 2007-2008 Yukon XL 1500 TCM can make your vehicle feel unreliable and unsafe. Look out for:
- ✔ Abrupt, harsh, or jerky gear changes.
- ✔ The vehicle getting stuck in a single gear, commonly known as “limp mode.”
- ✔ Delayed shifting when accelerating from a stop.
- ✔ An illuminated Check Engine Light or Transmission Warning Light, often with Diagnostic Trouble Codes (DTCs) like P0700 or various solenoid-related codes (e.g., P0750, P0751).
- ✔ A noticeable drop in fuel economy due to inefficient shifting.
- ✔ Complete loss of communication with the transmission, preventing it from shifting at all.
A Technician’s Notebook
I remember a 2008 Yukon XL 1500 that came into the bay with a really puzzling issue. The owner complained of intermittent stalling and a transmission that would randomly refuse to shift out of 2nd gear, but only after driving for 20-30 minutes. The codes were all over the place—solenoid faults, communication errors—but they’d clear and not return for days. After checking the wiring harness and fluid levels, which were fine, we focused on the TCM. Heat soak was causing an internal failure in the module. We installed a VIN-programmed T42 TCM, and the problem was solved instantly. It’s a classic failure mode for these units, and a new module is the only lasting fix.
A Straightforward Guide to Installation
One of the best parts about this module is its simple, plug-and-play design. For a 2007-2008 Yukon XL 1500, the installation is a breeze and can be done in your driveway in under 30 minutes with basic hand tools. No need to pay for hours of shop labor.
- Safety First: Always begin by disconnecting the negative terminal from your vehicle’s battery. This prevents electrical shorts and helps reset the vehicle’s computer systems.
- Locate the Module: On your Yukon XL 1500, the TCM is typically found in the engine compartment, mounted right next to the battery. It’s a black box with several large electrical connectors.
- Disconnect and Remove: Carefully unplug the electrical connectors. There may be locking tabs you need to release. Once disconnected, unbolt the module from its mounting bracket and remove it from the vehicle.
- Install the New Module: Bolt the new, pre-programmed TCM into the same location. Reconnect the electrical connectors, ensuring they click securely into place.
- Final Steps: Reconnect the negative battery terminal. While the module is pre-programmed, it’s good practice to use a basic OBD2 scan tool to clear any lingering fault codes from the system’s memory. Start the vehicle and enjoy your smooth-shifting transmission!
Verified Vehicle Compatibility
This T42 TCM is a direct replacement for a wide range of General Motors vehicles equipped with 4-speed automatic transmissions like the 4L60E, 4L65E, and 4L70E. While this page is focused on the 2007-2008 Yukon XL 1500 TCM, it also fits the following models. Please verify your specific application.
- GMC: Yukon, Yukon XL 1500, Sierra 1500/2500, Savana 1500/2500/3500, Envoy, Envoy XL, Canyon
- Chevrolet: Tahoe, Suburban 1500, Silverado 1500/2500, Avalanche 1500, Express 1500/2500/3500, Impala, Monte Carlo, Cobalt, HHR, Colorado, Trailblazer, SSR
- Cadillac: DTS
- Buick: LaCrosse, Lucerne, Allure, Rainier, Rendezvous
- Pontiac: G5, G6, Grand Prix, Pursuit
- Saturn: Vue, Aura, Ion
- Hummer: H3
- Saab: 9-7X
This part is interchangeable with service numbers: 24242391, 24234503, 24252114, 24230461, 24234274, 24235340, 24235754, 24238856, 24239224, 24239926, 24240400, 24241806, 24243901, 24255280, 24256960, and more.
Frequently Asked Questions
Do I need to program this module?
No! This is the biggest benefit. We program the module to your vehicle’s VIN before shipping. It arrives ready for installation, saving you a trip to the dealership and their programming fees.
How do I provide my vehicle’s VIN?
You can enter your VIN during the checkout process. Please double-check it for accuracy to ensure perfect programming for your specific vehicle.
Will this fix my transmission problems for good?
If your issues are caused by a faulty TCM, this part is the correct and lasting solution. It’s built to meet or exceed OEM specifications for reliability and performance, addressing the common failure points of the original module.
What is the warranty on this part?
This transmission control module comes with a one-year warranty, giving you peace of mind with your purchase.
Is this a difficult part for a DIYer to replace?
Not at all. For most vehicles, including the Yukon XL 1500, this is a very straightforward job that requires only basic tools and about 30 minutes of your time. Our installation guide above provides all the steps you need.