Frequently Asked Questions About GMC TopKick Truck Diesel Fuel Tanks

What fuel tank capacity options are available for GMC TopKick trucks?

GMC TopKick diesel fuel tanks typically range from 50 to 100 gallons, with the most common sizes being 50, 65, 80, and 100-gallon capacities. The right size depends on your specific TopKick model year and chassis configuration. C4500, C5500, C6500, and C7500 models may have different mounting brackets and space constraints. Always verify your truck's original tank dimensions and mounting points before ordering a replacement.

Will these fuel tanks fit my specific TopKick model year?

Fuel tank compatibility varies across TopKick production years (2003-2009). Most aftermarket tanks are designed to fit multiple years within this range, but mounting brackets, strap configurations, and sending unit connections can differ between early models (2003-2005) and later models (2006-2009). Check your VIN and original tank part number to ensure proper fitment. Some tanks require minor modifications to brackets or fuel line connections depending on your specific year.

What materials are these fuel tanks made from, and how do they compare to OEM?

Most replacement TopKick fuel tanks are constructed from either aluminized steel or aluminum. Aluminized steel tanks offer good corrosion resistance at a lower price point, while aluminum tanks provide superior longevity and weight savings but cost more. Both options typically match or exceed OEM specifications for wall thickness and pressure testing. Aluminum tanks are particularly recommended for trucks operating in high-salt environments or those requiring maximum weight reduction.

Can I install a replacement fuel tank myself, or do I need professional help?

While fuel tank replacement is possible for experienced DIY mechanics, it requires proper safety equipment and procedures. You'll need tank straps, new rubber isolators, fuel line disconnect tools, and potentially a transmission jack to safely lower and position the tank. The job typically takes 3-4 hours and involves disconnecting fuel lines, electrical connections for the sending unit, and filler neck hoses. Many customers choose professional installation due to the weight of filled tanks (up to 800 pounds when full) and the importance of proper fuel system connections.

Do these tanks come with sending units, straps, and mounting hardware?

Tank packages vary by manufacturer and price point. Basic replacement tanks typically include just the tank itself, requiring you to transfer your existing sending unit, fuel pump (if tank-mounted), and use your current straps and hardware. Complete tank kits include new sending units, mounting straps, and hardware, but cost more. Always verify what's included before ordering. If your original sending unit is functioning properly, a tank-only purchase can save money. However, given the labor involved in tank replacement, many customers opt for complete kits to avoid future sending unit failures.