Brother HL-4040CN Service Manual page 252

(7) Remove the Gear 20A from the Drive unit by releasing the Hook.
Hook
(8) Remove the Gear 33 from the Drive unit by releasing the Hook.
Hook
<Left side>
Gear 20A
Fig. 3-222
<Left side>
Gear 33
Fig. 3-223
3-144
Drive unit
Drive unit
Confidential