This AI-generated draft has not been independently verified for your vehicle. Confirm engine, trim, build date, tool fitment and torque specifications against the relevant service information before buying tools or starting work.
This is one of the easiest jobs on a T1 Silverado, with two small catches. The hold-down bolt is a 13 mm at the bottom of the battery, tucked against the fender, so you need a 6-10 inch extension and ideally a wobble to reach it — trying to do it with a short socket is the main reason this turns into a knuckle-busting half hour. Everything else is 10 mm.
The bigger thing people get wrong is the battery type. These trucks run Auto Stop/Start and a battery current sensor on the negative cable, and they expect an AGM battery (usually Group 48/H6). Drop in a bargain flooded battery and you will get short life, Stop/Start acting up, and sometimes charging complaints. Also do the battery sensor reset with a scan tool if you have one; without it the truck keeps charging for the battery it thinks it still has.
| Item | Type | Product search |
|---|---|---|
| Safety glasses Battery acid and sparks at the terminals. | Safety | search retailer |
| Nitrile gloves Keeps acid residue and corrosion off your hands. | Safety | search retailer |
| Memory saver OBD-II port or 12V socket type Keeps radio presets, HVAC, window/seat memory and learned data alive while the battery is out. | Recommended | search retailer |
| Ratchet 3/8 in drive, standard and stubby handy Drives the terminal and hold-down fasteners. | Required | search retailer |
| Socket 10 mm 6-point, 3/8 in drive Loosens the negative and positive cable clamp bolts. | Required | search retailer |
| Socket 13 mm 6-point, 3/8 in drive Removes the battery hold-down clamp bolt at the base of the battery. | Required | search retailer |
| Extensions 3/8 in drive, 6 in and 10 in The hold-down bolt is deep beside the battery and unreachable with a bare socket. | Required | search retailer |
| Universal swivel / wobble extension 3/8 in drive Helps line up on the hold-down bolt past the fender and cable routing. | Recommended | search retailer |
| Socket 8 mm, 1/4 in drive Some trucks have an 8 mm nut retaining the negative battery current sensor or a cable bracket. | Recommended | search retailer |
| Trim/panel pry tool Plastic Pops the plastic battery cover and any clipped wire looms without breaking tabs. | Recommended | search retailer |
| Battery terminal brush Post and clamp type Cleans corrosion off the cable clamps so the new battery makes solid contact. | Required | search retailer |
| Battery terminal spreader or flat screwdriver Gently opens a clamp that has been squeezed tight on the old post. | Recommended | search retailer |
| Battery carry strap or lifting handle A Group 48 AGM weighs 45-50 lb and sits down in a tray behind the fender. | Recommended | search retailer |
| Torque wrench 3/8 in drive, 5-80 ft-lb Terminal clamps strip or crush easily if over-tightened. | Recommended | search retailer |
| Battery terminal / corrosion cleaner spray Aerosol Neutralizes acid film on the tray and cable ends. | Consumables | search retailer |
| Terminal protectant grease or felt washers Dielectric/anti-corrosion Applied after tightening to slow future corrosion. | Consumables | search retailer |
| Replacement battery Group 48 (H6) AGM, ~730-760 CCA typical; verify your truck's group and type on the old label Auto Stop/Start trucks require AGM; flooded replacements cause premature failure and charging faults. | Parts | search retailer |
| Scan tool with GM battery replacement reset GDS2/MDI or capable aftermarket (e.g. bidirectional tool) Resets the battery sensor/state-of-health data so the charging system stops targeting an old, worn battery. | Recommended | search retailer |
Fastener sizes are the same on the 2.7L turbo, 5.3L, 6.2L and 3.0L Duramax — 10 mm terminals, 13 mm hold-down. The difference is count and size: 3.0L Duramax trucks and some dual-battery-optioned gas trucks have two batteries under the hood and should be replaced in matched pairs, while most single-battery trucks use a Group 48 (H6) AGM. A few configurations use a larger group size, so confirm against the label on the battery you pull out.
| Battery cable clamp bolts (10 mm) | about 11 ft-lb (15 Nm) — verify in the service manual |
| Battery hold-down clamp bolt (13 mm) | verify in the service manual |
| Negative current sensor nut (8 mm) | verify in the service manual |
Under the hood in the front corner of the engine bay, beneath a snap-on plastic cover. Trucks with the dual-battery setup (3.0L Duramax and some optioned gas trucks) have a second battery in the opposite front corner.
Yes on any truck with Auto Stop/Start, which is nearly all of them. The factory fitment is typically a Group 48/H6 AGM, and switching to a flooded battery usually leads to short life and Stop/Start or charging complaints.
There is no BMW-style mandatory coding, but GM does have a battery replacement/state-of-health reset in the BCM. Running it with GDS2 or a capable bidirectional scan tool makes the charging strategy treat the battery as new; without it, Stop/Start may stay off longer than normal.
A 10 mm socket for both cable clamp bolts and a 13 mm socket for the hold-down clamp bolt, plus a 6-10 inch 3/8 in extension to reach the hold-down. An 8 mm is handy if a cable bracket or the negative current sensor nut is in the way.