Truck Cap Windows | Replacement & Upgrade Windows
Our sliding side windows bring fresh air circulation and easy access to your truck cap interior without compromising security. Each window features tempered safety glass in a reinforced aluminum frame that matches the structural integrity of your ATC cap. The dual-latch system locks from inside, giving you control over ventilation while keeping cargo secure. These windows fit flush with your cap’s exterior profile, maintaining the clean aerodynamic lines that make ATC caps stand out on the road.
We engineer every sliding window to the same tolerances as our full cap assemblies, so installation is straightforward and weatherproofing stays tight season after season. The sliding panel glides on stainless steel tracks that resist corrosion and binding, even after years of use in rain, snow, and dust.
Window specs & installation
Glass construction and safety standards
Every window we manufacture starts with automotive-grade tempered glass that’s heat-treated to four times the strength of standard annealed glass. When tempered glass does break—usually from a sharp impact at an edge or corner—it shatters into small, blunt granules instead of sharp shards, reducing injury risk. This is the same safety glass used in vehicle side windows and meets all DOT requirements for highway use.
Our glass suppliers batch-test every production run for impact resistance, optical clarity, and thermal stress tolerance. We reject any glass that shows distortion, color variation, or surface defects. The tempered treatment also makes our windows more resistant to thermal shock, so you won’t see cracks from sudden temperature changes when you run the defroster on a frozen window or park in direct sun after air conditioning.
Frame materials and weatherproofing
We build every window frame from extruded aluminum that’s powder-coated to match your cap’s finish—white, black, or body-color-matched options. Aluminum won’t rust, even in coastal salt air or winter road-salt conditions, and the powder coating adds a second layer of corrosion resistance. The frames use a recessed gasket channel that holds EPDM rubber weatherstripping, the same material OEM automakers use for door seals and windshield gaskets.
EPDM stays flexible in temperature extremes from -40°F to 250°F, so the seal doesn’t crack in winter or go soft in desert heat. We pre-install the weatherstripping at the factory with butyl adhesive backing, so it won’t shift or fall out during shipping or installation. The gasket compresses evenly around the glass perimeter when you tighten the frame fasteners, creating a waterproof barrier that keeps rain, dust, and wind noise outside.
Installation and compatibility
All our replacement windows are cut to the exact dimensions of the original factory openings in ATC caps, so installation is a direct swap with no cutting, drilling, or frame modification. For sliding windows, you’ll remove the old frame assembly by backing out the perimeter screws, then drop the new window into place and secure it with the same screw holes. The process takes about 30 minutes per window with a cordless drill and a tube of silicone sealant for extra weatherproofing.
Fixed windows use a urethane adhesive installation similar to automotive windshield replacement. We ship these windows with a cartridge of the correct urethane formula and a plastic spreader tool. You’ll apply a continuous bead of adhesive around the frame perimeter, set the window into the opening, and secure it with temporary tape until the urethane cures—usually 24 hours. The cured urethane bond is stronger than mechanical fasteners and flexes with the cap structure during driving, preventing stress cracks.
Sliding, fixed, and tinted window options
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Common questions about truck cap windows
Our windows are precision-cut for ATC cap models and use ATC-specific frame mounting points, so they won’t fit caps from other manufacturers without modification. Each ATC cap series has unique window dimensions and fastener locations. If you need to match a competitor’s cap, you’ll need to provide exact measurements and we can discuss custom fabrication options, though lead times and costs are higher for non-standard builds.
For ATC owners, compatibility is straightforward: order by your cap model and year, and the window will drop into the existing opening. We keep dimensional records for every ATC cap we’ve manufactured since 1998, so we can match replacement windows to older units as long as you know your cap’s serial number or original purchase date.
Sliding window replacement is a DIY-friendly project if you’re comfortable using a cordless drill and following step-by-step instructions. You’ll remove the old frame, clean the mounting surface, apply a bead of silicone sealant, and secure the new window with the existing screw holes. Most truck owners complete the job in 30-45 minutes per window.
Fixed window installation requires more care because you’re working with urethane adhesive that needs proper surface prep and curing time. We include detailed instructions with every fixed window kit, and many DIYers successfully install them at home. If you’re not confident working with adhesives or don’t have a clean, temperature-controlled workspace for the 24-hour cure, a glass shop or auto body shop can install a fixed window in about an hour of shop time.
Bronze tint transmits about 35% of visible light, which gives you UV and heat protection while keeping the interior bright enough to see cargo details without turning on a flashlight. It’s a good match if your truck has factory-tinted rear glass or if you want heat reduction without a heavily darkened look.
Dark smoke tint transmits about 15% of visible light, offering maximum privacy and heat rejection. The interior will be noticeably darker, so you’ll rely more on interior lighting or a flashlight when loading gear in low-light conditions. Dark smoke matches well with blacked-out truck trim or if cargo concealment is a priority. Both tint levels block 99% of UV radiation, so the choice comes down to how much visible light reduction you want.
All ATC truck cap windows carry a lifetime warranty against glass breakage caused by manufacturing defects, including stress cracks, delamination, or spontaneous breakage unrelated to impact. The warranty also covers frame corrosion and weatherstripping adhesive failure for as long as you own the cap.
Impact damage from road debris, accidents, or vandalism isn’t covered, but we stock replacement glass and can ship it quickly. Tinted windows have an additional lifetime warranty against tint fading, peeling, or bubbling, since the tint is integrated into the glass rather than applied as a film. If a window fails under warranty, we’ll ship a replacement at no charge and provide installation support.
Our sliding windows use a compression gasket system that seals when the frame is properly tightened, and the EPDM weatherstripping stays flexible for years without cracking or shrinking. Leaks typically develop when the gasket accumulates dirt or the fasteners loosen from vibration, both of which are easy to fix.
We recommend cleaning the gasket channels twice a year and checking fastener torque annually. If you do see a leak, inspect the weatherstripping for compression set at the corners—if the gasket looks flattened or cracked, a replacement gasket kit takes about 15 minutes to install and costs a fraction of a new window. The frame-to-cap seal also benefits from a bead of silicone sealant applied during installation, which we call out in the instructions.
Yes, we offer retrofit kits for adding windows to solid-panel caps. The kit includes a window assembly, trim ring, fasteners, and a cardboard template for marking the cutout. You’ll use a jigsaw to cut the opening, smooth the edges with a file, and mount the window frame over the cutout with the trim ring covering the raw edge.
This is a more involved project than replacing an existing window—expect a few hours per side—but it’s a popular upgrade for owners who want better ventilation or visibility. The trickiest part is cutting a straight, clean opening; many owners clamp a straightedge guide to the cap panel to keep the jigsaw on track. Our customer service team can recommend local installers if you’d rather have a professional handle the cutout and installation.
We offer heated defroster grids on select fixed rear window models, typically for caps installed on trucks used in cold climates. The defroster grid is embedded in the glass and connects to your truck’s electrical system through a plug that mounts near the tailgate. This is the same technology used in automotive rear windows.
Heated windows require a compatible wiring harness, which we sell separately or can install at our factory if you order a new cap with the heated window option. Retrofitting a heated window to an existing cap is possible but involves running a new wire from the truck’s fuse box to the cap. We provide wiring diagrams and connectors, though many owners choose to have an auto electrician complete the install to ensure proper fusing and grounding.