Start with what is installed
Factory System Overview
This guide covers the GMT800 crew cab trucks, including the carryover 2007 Classic, not the redesigned 2007 GMT900. The body distinction matters because the dash, speakers and installation parts are not interchangeable across generations. Identify the truck before ordering a radio kit or enclosure.
Start with the installed options
Check for Bose amplification, separate tweeters, steering-wheel controls and any retained factory convenience features. Use the guide for your exact cab style; rear speaker locations and trim access differ.
Check depth as well as face size
These 2003-up dashboards accept a genuine double-DIN receiver, unlike earlier GM openings that only looked that size. The metal rear support still limits depth. A shallow digital-media receiver may avoid cutting that is needed for a deeper unit.
Planning guide, not a fitment guarantee. Match all adapters, wiring and removal procedures to your actual vehicle. Photographs show selected configurations, not every option package.
Radio Upgrade
Single-DIN and double-DIN receivers can be installed with the appropriate dash kit. The available opening is not the whole fitment story: the rear support and the new receiver’s chassis depth also matter. Test the proposed receiver before deciding whether support removal is necessary.
The warning chimes depend on the original radio. Specify a compatible integration interface that preserves those sounds and supplies switched 12-volt power. Match the harness to the actual factory system, especially when retaining a Bose amplifier. Steering-wheel audio buttons require a compatible receiver and control interface; test every button before closing the dash.
A flip-out receiver screen can interfere with the column-mounted shifter. Most deeper CD receivers need the rear support removed, while some shallow digital-media models may not. The supplied source also warns that replacing a Bose-equipped truck’s receiver can remove the mirror’s compass and temperature display. Verify that consequence for your exact configuration before committing to the installation.
Shop Speaker Sizes
Browse by location and size, then verify the fit for your truck.
Front doors • 6.5-inch or 6.75-inch factory woofers
Browse 6.5-inch coaxial speakersBrowse 5.25-inch coaxial speakersBrowse component speaker setsCheck year and system. Smaller alternatives need suitable adapters; 6.75-inch replacements require new mounting holes in the documented installation.
Front tweeters • door or Bose A-pillar
Browse car tweeters2003–2004 Bose tweeters are in the pillars. The later six-speaker arrangement has front-door tweeters. Secure custom mounts and verify wiring.
Rear doors • 5.25, 6.5 or 6.75-inch replacement options
Browse 5.25-inch coaxial speakersBrowse 6.5-inch coaxial speakersMatch the particular year and bracket. Smaller alternatives use adapters; the source calls for new holes with 6.75-inch replacements.
Rear-door tweeters • some upper-trim trucks
Browse car tweetersThe source confirms this location but does not document dimensions or removal. Measure and inspect it before selecting a replacement; fitment is not established here.
Collections are browsing categories, not guaranteed drop-in replacements. Confirm depth, mounting pattern, impedance, signal filtering and amplifier compatibility. There is no separate verified 6.75-inch collection here; the linked 6.5-inch category is a starting point for individually verified alternatives, not an equivalent-size claim.
Speaker Locations
The front speaker arrangement changes within this generation. Standard 2003–2004 trucks use 6.5-inch door speakers; the six-speaker system introduced in 2005 uses 6.75-inch front woofers with door tweeters. Some trucks also have pillar tweeters or a console subwoofer.
Front doors and component choices
Remove the sail panel and main door panel with care. A later woofer-and-tweeter system can be upgraded as a component set, but the tweeter needs a secure fabricated mount or suitable mounting straps. Check whether the particular 6.5-inch replacement needs an adapter rather than assuming all models share the same frame.
Pillar tweeters
On the documented 2003–2004 Bose setup, remove the pillar trim and release the tweeter from its grille. No dedicated wiring adapter is listed for this location. Use properly insulated connections and adapted mounts without obstructing any safety equipment.
Rear doors and window equipment
For manual windows, release the crank retaining clip before removing the door panel. Power-equipped panels need their wiring unplugged while supported. Verify mounting-screw supply before starting, and inspect the area behind any new mounting holes. The rear tweeters on some high-trim trucks remain an unverified detail, not a reason to guess their size.
Tools
Radio: panel tool, 7mm socket, ratchet and extension. Door speakers: panel tool, Phillips and small flat-blade screwdrivers, shop rag, 7mm socket, ratchet and extension. Use suitable drilling equipment and eye protection only where the chosen mount requires new holes.
Bass & Amplification
The optional Bose subwoofer sits in the center console and is a forward-firing dual-voice-coil driver. Reaching it means removing numerous trim pieces, and an aftermarket replacement requires a fabricated mount. A separately amplified compact sub or a correctly matched under-seat enclosure avoids treating this as a simple speaker swap. The source describes a specific 10-inch enclosure for a second-row 60/40 split bench, not universal clearance for every crew cab.
Choose the bass layout before buying
Browse amplified subwoofer modules Browse loaded subwoofer enclosures
These collections do not establish vehicle fit. Confirm enclosure dimensions, mounting, amplifier power and wiring requirements for the exact product.
Before You Put It Back Together
Before refitting panels, check every speaker, warning chime and retained control. Run the windows through their full travel and test the locks and door releases. Secure the wiring away from moving parts, then check for loose trim and rattles. Keep any removed factory hardware until the installation is complete.
Vehicle facts and reference photographs: Crutchfield Research Garage guide supplied by the owner. Written and organized for 12 Volt Outlet. Use current vehicle-specific service instructions for disassembly and safety precautions.
