Question 1

my drill sometimes just won't start, i pull the trigger and nothing happens, but if i whack it on the table it starts working

Accepted Answer

DIAGNOSIS You have an intermittent electrical connection. The most likely culprit is a cracked solder joint on the trigger switch's circuit board or a loose wire connection inside the handle. FIX Open the drill and inspect the trigger assembly connections.Remove battery and housing screws. Carefully open the clamshell halves. Check the wires from the battery terminals to the trigger, and from the trigger to the motor. Look for loose spade connectors. Reseat any loose connections. If you see a cracked solder joint on the trigger board, the whole trigger needs replacement. IF THAT DIDN'T WORK If connections are solid, the trigger/switch unit itself is failing intermittently. The physical impact temporarily reconnects internal contacts. Replace the trigger switch assembly. HEADS UP The "percussive maintenance" (whacking it) is a temporary fix that worsens the problem. Each impact can loosen other connections or crack plastic housing clips, leading to more failures.

Question 2

the chuck on my drill is seized shut, can't open it to change the bit no matter how hard i twist

Accepted Answer

DIAGNOSIS Internal corrosion or debris has locked the chuck's jaws. This happens after exposure to moisture or if metal shavings worked their way inside during use. FIX Break the corrosion free.Put a large Allen key or chuck key in the jaws. Gently tap the end of the key with a hammer in the direction to *open* the chuck (counter-clockwise). The shock often breaks the bond. If it moves slightly, spray penetrating oil (like PB Blaster) into the seams and work it back and forth. IF THAT DIDN'T WORK If tapping and oil don't free it, the chuck is permanently frozen. You'll need to replace it, which may require cutting it off if the left-hand screw inside is also seized. Use a Dremel to carefully cut a slot in the chuck body and split it. HEADS UP Do not put the drill in a vise and apply extreme torque to the chuck body. You will twist and damage the spindle, which is a much more expensive repair (requires a new transmission).

Question 3

dewalt drill smells like burning and gets really hot near the motor just holding the trigger for a few seconds

Accepted Answer

DIAGNOSIS The motor is overheating due to a short or excessive friction. This is often a failing armature (the spinning part of the motor) or worn motor bearings creating drag. FIX Stop using it immediately. Replace the motor assembly.Remove battery and housing screws. Separate the motor/trigger unit from the transmission. Disconnect the motor wires (note their positions). Swap in the new motor, reconnect wires, and reassemble. IF THAT DIDN'T WORK If a new motor also overheats, the fault is in the trigger/switch assembly. It might be sending erratic voltage, causing the motor to over-amp. Replace the trigger switch module. HEADS UP The burning smell is insulation melting on the motor windings. This is a critical failure. Continuing to use it is a fire risk and will completely destroy the motor, making it un-repairable.

Question 4

the forward/reverse switch on my dcd771 is super stiff and sometimes gets stuck in the middle

Accepted Answer

DIAGNOSIS Debris (sawdust, drywall dust, metal shavings) has packed into the switch mechanism. The switch slides a physical bar that hits microswitches inside; grit jams it. FIX Clean it out.Remove the battery. Use compressed air to blast around the base of the switch. Spray a small amount of electrical contact cleaner (not WD-40) into the switch slot while working it back and forth. Let it dry completely before using. IF THAT DIDN'T WORK If cleaning doesn't free it, the switch mechanism itself is broken or the internal plastic slide is cracked. This requires replacing the entire switch/trigger assembly, which is sold as one part. HEADS UP Never force the switch. A switch stuck in the middle breaks the electrical connection, which can mimic a dead battery or trigger failure. Forcing it can snap the internal plastic lever.

Question 5

my drill works on speed 2 but makes a horrible grinding noise and barely moves on speed 1

Accepted Answer

DIAGNOSIS The speed selector ring is engaging, but the gear train for low speed (Speed 1) is damaged. A common failure point is the small pinion gear that engages when you slide the selector. FIX Replace the transmission assembly. The gears for both speeds are housed together in one sealed unit.Remove battery and housing screws. Separate the motor housing from the gear housing. Swap the old transmission for a new one. The speed selector ring transfers over. Reassemble. The repair fixes both speeds. IF THAT DIDN'T WORK If the noise persists with a new transmission, the issue is the motor itself. The armature might be damaged and only partially engaging under the high torque demand of Speed 1. HEADS UP Forcing the drill to work in Speed 1 while it's grinding will destroy the transmission housing. You'll go from needing a $40 transmission to needing a whole new drill body.

Question 6

the battery meter on my dewalt 20v drill only shows one bar even after a full charge, is the drill broken

Accepted Answer

DIAGNOSIS The drill is fine. This is a battery pack issue. One or more cells inside the pack are failing, causing the battery's internal management system to report low voltage under load. FIX Test with a different, known-good DeWalt 20V Max battery. If the drill works normally and shows a correct charge with the other battery, you've confirmed the first battery pack is faulty. Replace the battery. IF THAT DIDN'T WORK If multiple batteries show the same one-bar symptom in this drill but work fine in another DeWalt tool, then the problem is in the drill's battery terminal contacts or the circuit board that reads the battery data. Clean the contacts first with isopropyl alcohol. HEADS UP Do not continue using a battery that shows one bar when you know it's charged. It can fail catastrophically (overheat, swell). A swelling battery is a fire hazard—dispose of it properly immediately.

Question 7

dewalt dcd771 chuck wobbles and bits won't stay tight, it's not the bit itself

Accepted Answer

DIAGNOSIS The chuck's internal jaws are worn or the spindle it mounts to is bent. Wear from heavy side pressure or dropping the tool is the most common cause. FIX Replace the chuck. It's a direct job.Open the chuck fully. Look inside for a left-hand threaded screw (turns clockwise to loosen). Secure that screw, then use a large Allen key or chuck key in the jaws to unscrew the entire chuck (standard right-hand threads). Screw the new chuck on hand-tight, then tighten the left-hand screw inside. IF THAT DIDN'T WORK If a new chuck still wobbles, the spindle shaft itself is bent. This requires replacing the entire transmission assembly, as the spindle is part of it. HEADS UP When installing the new chuck, do NOT use an impact wrench. Hand-tighten with the Allen key. Over-torquing can strip the spindle threads, forcing a full transmission replacement.

Question 8

my dewalt 20v drill just clicks when i pull the trigger, battery is charged and it feels like it's trying but nothing spins

Accepted Answer

DIAGNOSIS The motor is getting power but the mechanical connection to the chuck is broken. This is almost always a stripped planetary gear in the transmission. FIX Replace the transmission assembly. It's a single module.Remove the battery. Take out the long screws from the gear housing. Separate the motor/trigger housing from the transmission housing. The old transmission lifts out; drop the new one in. Reassemble. No gear alignment needed. IF THAT DIDN'T WORK If the transmission is new and it still just clicks, the issue is upstream. The motor armature might have failed or the trigger/switch assembly is faulty and not sending full power. HEADS UP Don't run the drill in this state. The clicking is metal teeth grinding. Continuing will turn a simple gear replacement into a need to replace the entire gearbox shell and possibly the motor.

DeWalt 20V Max Cordless Drill DCD771C2

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