Milwaukee M18 1/4 in. Compact Brushless 3-Speed Impact Driver (Bare Tool)

Milwaukee M18 1/4 in. Compact Brushless 3-Speed Impact Driver (Bare Tool)

By Milwaukee · Impact Drivers · Power Tools

  • Compact brushless: 3-speed DRIVE CONTROL
  • 1/4 in. hex quick-change chuck
  • Only 4.9 in. long, 2.6 lbs bare
  • Self-tapping screw mode
  • M18 REDLITHIUM battery compatible (sold separately)

Lowest price seen
$159.00
from $159.00 at MaxTool · Checked Oct 8, 2026

Prices are snapshots. Check the current price with the store.

Summary

A short, light M18 impact driver with three selectable speed ranges, sold tool-only. It is not M18 FUEL, so compare it with the 3650-20 and 2953-20 before you pay for the extra speed selector.

Strengths

  • At 4.4 inches and 1.7 lb bare, it is much shorter and lighter than the earlier M18 compact 2850.
  • Modes 1 and 2 lower the top speed and impact rate for control; mode 3 gives the full 3,600 RPM.
  • Existing M18 owners need no second battery platform.
  • An owner reported about 1.5 years of trouble-free use from late 2023.
  • The factory diagram lists front-collet, belt-clip and gearcase service parts, so repairs are identifiable.
  • A compact M18 pack keeps the working weight and base width down.

Weaknesses

  • It is not M18 FUEL; the 2953-20 costs only $20 more at Home Depot.
  • The 1/4-inch hex collet cannot hold smooth round-shank drill bits without an adapter.
  • There is no dedicated self-tapping-screw mode.
  • A March 2026 owner reported overheating and lockup, then the same symptoms on a warranty replacement.
  • Tool-only means a battery and charger add real cost.
  • A high-capacity M18 pack adds weight and base width.

Verified specifications

IdentityMilwaukee 3651-20, M18 Compact Brushless 1/4-inch Hex 3-Speed Impact Driver; tool-only.
Drive1/4-inch hex quick-release collet; pull the collar outward to insert or remove a bit.
Motorbrushless with REDLINK control and an all-metal gear case; 1,700 in-lb (about 142 ft-lb) claimed peak torque.
Speeds0–1,250 RPM / 0–2,500 IPM; 0–2,400 RPM / 0–4,700 IPM; 0–3,600 RPM / 0–4,900 IPM.
Modesthree selectable ranges with a variable-speed trigger; no separate self-tapping-screw mode.
Dimensions4.4-inch head length, 2.1-inch width, 1.7 lb bare; 7.7-inch height listed by Home Depot.
BatteryM18 REDLITHIUM 18V packs and an M18 charger; M12 packs do not fit.
Boxone tool with belt clip and work LED; no battery, charger, case or bits.
Temperature and servicerecommended 0–125°F; service inspection suggested every six months to one year.
Service referencebulletin 54-26-2885R (June 2024), serial prefix N61A.
Full research notes and sources

Speed settings and control

Three ranges cover 0–1,250 RPM / 0–2,500 IPM, 0–2,400 RPM / 0–4,700 IPM, and 0–3,600 RPM / 0–4,900 IPM; the trigger varies speed within each range, and the selector should move only after the motor stops. These are speed ranges, not three calibrated torque stops, and mode 1 does not auto-detect a self-tapping screw the way some four-mode FUEL tools do. Impact tightening time changes final tension, so use a hand torque wrench for a specified torque and never rely on this driver for wheel lug nuts. The 1/4-inch hex collet needs a hex-shank adapter for ordinary round drill bits.

Problems owners report

There is no published failure rate for this exact model. The clearest warning is a verified March 21, 2026 review: the tool became unusually hot on light tasks, seized and would not spin, and the warranty replacement showed the same symptoms; Milwaukee replied on March 25 that it would follow up, with no final resolution posted. Another owner on June 27, 2025 found the forward/reverse switch awkward to reach into forward with one thumb. An April 11, 2026 r/Tools poster only speculated that the small motor envelope and vents might run hot and asked for real feedback. Owners also report driving deck screws and about 1.5 years of trouble-free use, so treat these as individual cases rather than a defect pattern. If the tool overheats or locks up, stop, remove the battery and follow Milwaukee’s service process; clean and dry the battery contacts if it will not run at full power with a charged pack.

Battery, parts and running costs

There is no subscription or scheduled cartridge or filter, and the brushless motor has no periodic carbon-brush service. A 2.0-Ah M18 compact battery, 48-11-1820, is $119 at Home Depot and is not included; the M12/M18 charger 48-59-1812 is $89. A belt clip kit, 42-70-0950, is $5.95 at Home Depot Repair Parts, $6.67 at PartSelect and listed at $4.36 out of stock at Power Tool Repair. Collet pieces are $2.00 for the washer, $2.00 for the spring and $4.24 for the sleeve at Power Tool Repair, all out of stock; a gearcase and anvil kit, 14-29-9005, is $49.45 out of stock, and a rotor assembly, 14-46-9865, is $27.49 with one in stock. A PCBA and motor stator assembly, 14-20-9330, is listed around $101.09 out of stock, which is close to replacement-tool money, so check the five-year warranty before buying it. For energy, 100 full 2.0-Ah cycles is 18 V × 2 Ah × 100 = 3.6 kWh of stored energy a year, and at an assumed $0.25 per kWh that is only about $0.90 of equivalent electricity before charging losses, not a measured wall cost.

Prices and which model to buy

In October 2026 the 3651-20 was $159 at Home Depot and Acme Tools, the latter on backorder, and $159 at Power Tool Repair out of stock with a 14-day lead time. Pro Tool Reviews listed the 2023 launch at $149 for the three-speed model, which is historical, not a checkout price. A September 10, 2026 used listing showed a $65.93 median asking price across 23 listings, not verified sales. The one-speed 3650-20 was $149 at Home Depot and the four-mode M18 FUEL 2953-20 was $179, both bare, so the FUEL model is better for demanding driving while the 3651 keeps the shortest body. At the checked $159, an M18 owner who needs control in tight spots should pick the 3651-20; if the speed selector has no value, the 3650-20 saves $10.

Support and warranty

Milwaukee covers the 3651-20 with a five-year limited power-tool warranty through authorized distribution, excluding normal wear, misuse, accidents and unauthorized repair; battery packs have their own coverage. Keep a dated receipt, or Milwaukee may use the manufacturing date. eService lets eligible US owners create and track repair orders, advertises roughly 7–10 business days and free shipping for eligible repairs, and some products are not eligible; otherwise call 1-800-SAWDUST (1-800-729-3878). A third-party repair listing shows a one-year warranty badge that conflicts with the maker’s five-year tool warranty, so confirm the source if buying reconditioned.

Sources

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Independent reviews:

Owner reports:

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