How to Replace the Transmission on a DeWALT Cordless Drill

Finish Nailer Repair - Replacing the Driver Guide (Ridgid Part # 79004001022)

Replacing the transmission on a Dewalt drill

The Facts

Transmission trouble? It's time to face the fix. Whether you are a master carpenter or an occasional drill-seeker, eReplacementParts.com provides the parts, procedures and facts you need to fearlessly fix what fails you.

The transmission accomplishes two primary tasks inside your cordless hammer drill. First, it converts the (high RPM) output from the motor into (low RPM) torque. Second, it contains the gear shift lever for the high, medium and low speed gears. When the transmission goes bad in your hammer drill, you'll likely notice decreased rotation at the chuck (spindle) despite sufficient output from the motor.

You may also notice one (or more) of the speeds in the gearbox quits working. Be careful not to confuse these problems with a gearbox (selector switch) that is simply "stuck" between gears, because this will produce the same type of symptoms.

This article provides step-by-step instructions for removing and installing the transmission on a DeWALT cordless hammer drill.

Let's get started.

The Fix

REMOVING THE TRANSMISSION [top]

1. Remove the battery.

Remove the battery from the drill.

Remove the battery

 

 

 

2. Remove the end cap.

Remove the (4) screws from the end cap.

Remove the screws

 

 

Remove the end cap from the drill.

Remove the end cap

 

 

 

3. Remove the gear case assembly.

Remove the (4) screws from the gear case assembly.

Remove the screws

 

 

Separate the gear case assembly from the motor housing.

Remove the gear case

 

 

 

4. Remove the top half of the clamshell (housing).

Remove the (5) screws from the clamshell assembly.

Remove the screws

 

 

Lift the top half of the clamshell (housing) away from the lower half.

Remove the clamshell

 

 

 

5. Remove the transmission.

Use one hand to hold the motor assembly in place within the lower housing.

Hold the motor

 

 

Lift and separate the transmission from the motor assembly.

Remove the transmission

 

 

 

INSTALLING THE NEW TRANSMISSION [top]

6. Install the new transmission.

Remove the rubber band (if equipped) from the new transmission assembly.

Remove the band

 

 

Align the gears of the new transmission with the pinion gear (on the motor).

Align the gears

 

 

When properly aligned, the transmission/motor assembly should “lock” into the housing.

Lock into place

 

 

 

REASSEMBLING THE UNIT [top]

7. Reinstall the top half of the clamshell (housing).

Install the top half of the clamshell (housing).

Install Clamshell

 

 

Secure the clamshell assembly with the (5) screws.

Secure the clamshell

8. Reinstall the gear case assembly.

Install the gear case assembly.

Install the gear case

 

 

Rotate the spindle shaft (chuck) until the gear box aligns (snaps into place) with the motor housing.

Rotate the shaft

 

 

Secure the gear case to the motor housing with the (4) screws.

Secure gear box

 

 

 

9. Reinstall the end cap.

Install the end cap.

Install end cap

 

 

Secure the end cap with the (4) screws.

Secure the end cap

 

 

 

10. Reinstall the battery.

Install the battery.

Replace battery

 

The Finish

As you just learned, fixing things yourself means more drilling with less billing. Hopefully, this article has restored your ability to drill holes without replacing your whole drill. And that's just the tip of the bit. Our online repair guides can help expand your skills far beyond drills; empowering you to face power tool problems whenever they arise; and to fearlessly fix whatever fails you.

Find your next fix here.

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