Milwaukee 2658-20 M18 3/8 Impact Wrench

The Verdict

The Milwaukee 2658-20 isn’t the most powerful impact wrench in the M18 lineup — and that’s exactly why you might want it.

This 3/8-inch compact impact wrench fills the gap between a bulky 1/2-inch beast and a weak electric screwdriver. It’s the tool you grab when you’re contorted under a dash, fighting a caliper bracket bolt, or swapping a serpentine belt tensioner. As shown in the product image, the 5.1-inch overall length (without battery) is the headline feature — that’s barely longer than a standard ratchet.

What’s in the box: Just the bare tool. No battery, no charger, no case. Milwaukee sells this as a kit-less add-on for people already invested in the M18 platform. If you’re starting from scratch, factor in the cost of at least one 2.0Ah or 5.0Ah battery and a charger — that’s another $100–$150 on top of the wrench’s street price.

Real-world performance: The 2658-20 specs out at 150 ft-lbs of nut-busting torque and 100 ft-lbs of fastening torque. In practice, that means it zips off 10mm through 15mm bolts with authority — think suspension links, alternator brackets, and exhaust hangers. The four-position power management switch (via a rotary dial near the base) lets you dial down to 25 ft-lbs for plastic trim or delicate work, which is a genuinely useful feature.

The friction ring socket retainer is the quiet hero here. Unlike the older hog-ring style that chews up socket anvils, this one holds sockets snug without requiring a punch or pliers to remove. One-handed socket changes work as advertised.

What buyers consistently praise: The size-to-power ratio dominates the feedback. One verified owner wrote, “I’ve used it on engine mounts and AC compressors where my 1/2-inch couldn’t physically fit. It’s become my most-used wrench.” Another noted, “Battery life is impressive — I did a full brake job on a 3.0L F-150 with a single 2.0Ah pack and still had juice left.” The build quality also gets frequent mention — the all-metal gear case and rubber overmold feel like they’ll survive a drop from a lift.

Where it falls short: Let’s be direct about the torque ceiling. At 150 ft-lbs, this won’t crack lug nuts torqued to 100+ ft-lbs on most pickups and SUVs. You’ll still need a breaker bar or a 1/2-inch impact for wheel work. The variable-speed trigger also has a learning curve — it’s easy to overshoot into full speed when you’re trying to snug something gently. And as a bare tool, it’s only a good value if you’re already in the M18 ecosystem. One reviewer summed it up: “Great tool, but be aware of what it isn’t — this is a mid-torque, not a high-torque.”

Who should buy this:

• Weekend DIYers doing brakes, suspension, and engine work on cars or light trucks
• Professional mechanics who need a second, compact impact for tight spots
• RV/boat owners working in cramped compartments where full-size tools won’t fit

Skip it if you primarily need lug nut removal, work on heavy-duty commercial vehicles, or don’t already own M18 batteries.

FAQ:

Q: Will this remove lug nuts?
A: On most sedans and crossovers with lug nuts torqued to 80–100 ft-lbs, yes — but it’ll struggle and may stall on trucks torqued to 120+ ft-lbs. Plan accordingly.

Q: Does it come with a battery?
A: No. This is a bare tool. You need an M18 battery and charger sold separately.

Q: What’s the difference between this and the 1/4-inch hex version?
A: The 3/8-inch square drive accepts standard sockets and delivers more torque (150 vs. 100 ft-lbs). The hex version is for screwdriver bits and smaller fasteners.

The Verdict:

Buy it if you need a compact, reliable 3/8-inch impact for tight spaces and already run M18 gear. It’s a legitimate shop upgrade.

Skip it if you need lug nut torque, want an all-in-one kit, or are starting fresh on a battery platform — buy a 1/2-inch high-torque model instead.

Rating: 4.6/5 — It’s not the tool for every job, but for its intended niche, it’s outstanding. The limitations are honest ones, not defects.

Where to Buy

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Last updated: 2026-08-06. Ratings and prices current as of review date. Verify on Amazon before purchasing.