The bolt-on sliders in the companion guide are right for the majority of 4Runner builds. This card is for the owner who genuinely puts the body on rock — where a weld-on or weld-reinforced hybrid carries far more load without distorting the pinch seam. It is more capable and considerably more committing to install.
A bolt-on slider clamps and through-bolts to the pinch seam and handles steps, curbs, and the occasional rub. It is enough for most trucks and it is reversible.
A weld-on ties the slider directly into the frame rail and rocker structure, so it shrugs off being loaded with the truck's full weight on a rock, being used as a high-lift point, or taking a hard drop onto a ledge. On a 4Runner that uses the slider as armor rather than as a step, the welded joint is what keeps repeated loading from eventually opening the pinch seam.
The honest test: if you have ever set the truck down on a slider and heard the body creak, or if you plan trails where the rocker will contact rock rather than clear it, the weld-on is the right answer. If you mostly want a step and protection from parking-lot and forest-road hazards, the bolt-on version is the better spend.
Two spec lines separate a good slider from a decorative one:
Tubing. Look for DOM (drawn over mandrel) tube, typically 1.75 in x 0.120-0.250 in wall, rather than welded HREW. DOM has no seam to concentrate stress and tolerates impact without cracking at the weld. A vendor that does not state the tube type on the product page is telling you something.
Plate and gusseting. The frame-side mounting plate should be at least 3/16 in and should spread load across two or more frame crossmember areas, not a single point. Count the frame attachment points: three per side is the minimum worth buying, four is better.
Geometry is the other half. A kick-out design adds a usable step and a wider footprint for stepping into a lifted truck, but it catches on tight rock and it is the first thing to bend on a narrow trail. A flush, tucked design protects better on a true crawler and keeps the truck narrow. Pick around how you wheel, not how it looks parked.
Plan a full day. This is fabrication, not bolt-on.
Park level, chock the wheels, and set the truck on jack stands under the frame so the body sits at its natural ride height. Welding a slider with the body loaded differently than it sits is how door gaps end up wrong.
Remove the plastic rocker cladding and any mud flaps. Pull back the fender liners at both ends of the rocker so you can see the pinch seam and the frame rails.
Strip paint, seam sealer, and undercoating from every weld area down to bright metal with a flap disc. Weld-through primer goes on immediately after — bare steel starts flash rusting within the hour.
Dry-fit and support the slider on a floor jack. Set the fore-aft position off the door openings, not off the wheel arches. Check tire clearance at full lock and at full compression, and confirm the slider is level to the rocker with a magnetic level.
Tack at four points per side, then step back and re-measure. Compare left to right, check door gaps, and open and close both doors. Tacks are cheap to grind off; a full weld is not.
Weld out in short stitches, alternating ends, letting the panel cool between passes. Continuous heat in one area warps the rocker and telegraphs through the paint.
Dress the welds, prime, paint, and seam-seal every cut edge.
Spray cavity wax or an internal frame coating into the rocker and frame cavity through the factory drain holes. This is the step most installs skip and the reason welded sliders rust from the inside on salt-belt trucks.
Airbag sensors. 5th gen 4Runners carry side-impact sensors near the B-pillar and rocker area. Disconnect the battery and wait at least 90 seconds before grinding or welding near them, and keep the welding ground clamp on the frame close to the weld so current does not route through body electronics.
Fuel and brake lines. Both run along the frame rail on the driver side. Trace and shield them before an arc gets anywhere near.
Fire watch. Sound deadening, the carpet edge, and the wiring loom behind the rocker all burn. Have an extinguisher within reach and a helper watching the interior side.
KDSS trucks. On a KDSS-equipped 4Runner the hydraulic lines and the sway bar linkage live in this area. Confirm clearance before you weld and re-check after; the KDSS service guide covers what those lines do and why pinching one is expensive.
Rust. On any truck older than about ten years, inspect the rocker and frame for scale before you commit. Welding new steel to a rusted seam moves the failure point rather than fixing it. The frame rust guide covers how to judge what you are looking at.
If you cannot weld, do not improvise. A shop session at $400-600 or a quality bolt-on is the honest alternative — a poor weld on a structural mount is worse than no weld.
As of 2026, weld-on and hybrid sliders for a 4th or 5th gen 4Runner run roughly $700-1,200 a pair bare, plus $150-350 for powder coat if not included. Consumables, weld-through primer, and cavity wax add $50-80. A fab shop that welds customer-supplied sliders typically charges $400-600 for the pair.
All-in that is $900-1,700 done at home, or $1,200-2,200 with shop labor — against roughly $500-900 installed for a quality bolt-on. Pair them with proper skid plates; sliders protect the rockers, not the drivetrain underneath.
Step up to weld-on or hybrid sliders only if you load the body on rock — the bolt-on is plenty for most 4Runners. Insist on DOM tube, at least 3/16 in mounting plates, and three or more frame attachment points per side. Prep to bright metal, tack and measure before you weld out, and wax the rocker cavity afterward. Done properly, it is the last slider the truck will ever need.
Written and maintained by an AZ wheeler and driveway wrencher. Always cross-reference your factory service manual — modifications affect vehicle safety and warranty. Work at your own risk.