Start with what is installed
Factory System Overview
The 2007–2013 extended-cab Silverado and Sierra were offered with standard and Bose audio. The standard door speakers are 4-ohm units. Bose changes the electrical requirements: the documented front speakers are approximately 1.9 ohms, while the rears are approximately 3.6 ohms. Identify the system before selecting replacements, especially if the original amplifier will stay. A speaker that physically fits is not necessarily an electrical match.
Identify your vehicle and equipment
This guide covers the GMT900 body, not the previous GMT800 sold as a 2007 Classic. The two generations overlapped, so check the cab and dashboard rather than ordering from model year alone. Some trucks have front-pillar tweeters, and Bose-equipped examples also have a console woofer and amplifier.
Radio Upgrade
Two dashboards appear in this cab. Type A places vents beside the radio; Type B places them above it. Both can accept single-DIN and suitable double-DIN receivers with the correct installation kit. The dash structure can interfere with plugs at the upper rear of a deep receiver. A chassis less than 6½ inches deep, or one with its rear connectors lower down, is worth checking against the available space before purchase.
Release the radio trim carefully because its metal clips are tight. The Type A arrangement uses six 7mm screws across the switch panel, climate controls and radio; Type B uses eight. Disconnect the receiver only after the surrounding parts are supported and the connectors are accessible. Use a vehicle-specific interface to preserve warning chimes and applicable OnStar functions, and confirm the turn-signal relay and steering-wheel-control requirements. Do not assume a basic wiring harness retains these functions.
Speaker Locations and Sizes
Shop Speaker Sizes
Choose the documented location and size, then verify the individual product.
Front doors • 6½ or 6¾ inches
6½-inch Coaxial SpeakersBrowse Speakers • verify 6¾-inch fitConfirm brackets, depth, impedance and the retained amplifier. A collection is not a direct-fit guarantee.
Rear doors • 6½ or 6¾ inches
6½-inch Coaxial SpeakersBrowse Speakers • verify 6¾-inch fitConfirm brackets, depth, impedance and the retained amplifier. A collection is not a direct-fit guarantee.
Front pillars • tweeters, if equipped
Car TweetersConfirm brackets, depth, impedance and the retained amplifier. A collection is not a direct-fit guarantee.
Nominal size is only a starting point. Confirm exact basket dimensions, mounting, wiring, crossover and amplifier compatibility. Coaxial speakers, midranges and subwoofers are not interchangeable. There is no dedicated 6¾-inch collection linked here; check actual product dimensions in the general speaker collection.
Front doors
The original nonstandard GM basket is close to a 6¾-inch speaker. Both 6½-inch and 6¾-inch replacements are documented, but adapter plates are required. Standard-system harness adapters can simplify the connection. The Bose front location needs an appropriate wiring solution and roughly 2-ohm replacements if retaining the factory amplifier and its output balance. Verify the actual speaker rather than assuming all door wiring is the same.
Rear doors
The extended cab uses rear-door speakers, not the rear-pillar layout of a regular cab. The documented replacement sizes are 6½ and 6¾ inches with adapters. Standard rears are 4 ohms; the approximately 3.6-ohm Bose rears can use suitable 4-ohm replacements. Plan secure connections for Bose wiring. Check whether your truck has manual or power windows before beginning panel removal.
Front-pillar tweeters, if equipped
These small speakers need a fabricated or universal mounting solution rather than an assumed direct-fit bracket. The source does not specify a universal replacement diameter. No plug-in harness is documented here, so plan secure insulated connections. Retain the correct crossover arrangement when installing component tweeters.
Tools and Preparation
Radio: panel tool and 7mm socket/ratchet. Doors: panel tool, 7mm and 10mm drivers, flat-blade screwdriver and needle-nose pliers; front-door work may also need a drill and ⅛-inch bit. Pillar tweeters: small flat-blade screwdriver. Protect wiring and window mechanisms before drilling.
This overview is for planning, not a substitute for complete vehicle-specific service and disassembly instructions. Protect trim, keep hardware organized and check behind every drilling location. Do not disturb airbag equipment or leave pillar retainers disconnected.
Bass and Amplifier
The Bose woofer and amplifier sit in the center console. Access is extensive enough that adding a separate enclosure can be more practical than dismantling the console to replace the original woofer. The source does not establish a standard drop-in subwoofer size for this location. Choose a cab-specific enclosure or measure an alternative position, allowing clearance for seat movement and passengers.
Under-seat and behind-seat spaces may accommodate amplifiers or compact bass equipment, but measure your truck before choosing a box. An extended-cab enclosure is not automatically interchangeable with crew-cab hardware. If bypassing Bose amplification, plan the signal path, speaker wiring and amplifier power as a complete system, not just a disconnected factory woofer.
Installation Checklist
Finish the job with functional checks, not just a listening test.
- Confirm year, body style and factory audio package
- Verify warning chimes and required retention interfaces
- Check receiver depth and rear-plug clearance
- Match speaker size, mounting and electrical load
- Secure all wiring and protect it from moving parts
- Test every speaker before closing the panels
- Check windows, locks and door releases after assembly
- Recheck retained controls and bass-system operation
Keep a record. Save part numbers, interface settings and wiring changes for future service.
Car audio guides, upgrades and installation planning.
