Start with what is installed
Factory System Overview
This guide covers the GMT800 extended 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.
The supplied guide identifies rear-support removal for receivers deeper than 6-3/8 inches. Flip-out screens are unsuitable because the dashboard overhang prevents normal opening. Retaining Bose, OnStar and warning chimes requires the appropriate interface. Replacing the original radio also removes its factory satellite-radio function; assess a separate compatible tuner if that feature matters.
Shop Speaker Sizes
Browse by location and size, then verify the fit for your truck.
Front doors • 6.5-inch factory speakers
Browse 6.5-inch coaxial speakersBrowse 5.25-inch coaxial speakers5.25- or 6.5-inch alternatives use the appropriate mounting adapter. Some 6.75-inch replacements require new holes.
Front tweeters • Bose pillars / some standard doors
Browse car tweetersBose tweeters are in the A-pillars; some non-Bose trucks have a tweeter beside the door woofer. Confirm actual equipment and mounting.
Rear doors • 4×6-inch openings
Browse 4×6-inch speakersBrowse 4-inch speakersBrowse 3.5-inch speakersThe source supports 4×6-inch, plate-style, 4-inch and 3.5-inch alternatives with the required mounting work. Bose uses a round driver on a 4×6-inch bracket.
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 doors use 6.5-inch stock speakers. Extended-cab rear doors use 4×6-inch units, while the Bose rear driver is round and mounted in a 4×6-inch bracket. Those rear doors are a key difference from a crew cab.
Front-door access and adapters
The front speakers use clip-in plates once the door panels are removed. A bracket is needed for the documented smaller alternatives. Check whether the chosen 6.75-inch model requires drilling, and inspect behind each proposed hole before making it.
Bose pillar tweeters
Remove the trim carefully to reach the tweeters. Replacement tweeters need secure adapted mounts, such as suitable universal mounting straps or the tweeter maker’s brackets. The factory grille location does not establish that every aftermarket tweeter will fit.
Rear-door mounting and sealing
After the rear panel is released, the original clip-in speaker plate is accessible. New mounting holes are required for the replacement arrangements described in the source. Seal frame gaps appropriately so the speaker does not sit over an open air leak; preserve clearance for trim and wiring.
Tools
Radio work: panel tool, 7mm socket, ratchet and extension; a suitable hacksaw blade only if confirmed support removal is needed. Speaker work adds Phillips and flat-blade screwdrivers, a drill with 1/8-inch bit and a Torx T20 driver for 2005-up trucks.
Bass & Amplification
Some later Bose trucks have a powered subwoofer in the center console. Access involves extensive disassembly, and replacing the original sub with an aftermarket unit also calls for a new amplifier. A cab-specific enclosure can be a more practical alternative, but confirm seat arrangement and usable space before selecting it.
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.
