For Model ZW120-6 as mentioned above:
Drive Motor and Final Drive Transmission
in the following steps refer to the Arm Cylinder illustration on page 38
848 Pages (TM14288X19)
2120 Technical Manual: 658 Pages
Caterpillar CAT 320C, 320C L, 320C LN, 320C S Excavator Service Repair Manual (BEA00001 and up) For Model ZW120-6 as mentionedFormat : PDF SUPPLIED AS DOWNLOADABLE LINK Excavator Model: 320C, 320C L, 320C LN, 320C S Serial Applicable: BEA00001 and up Language English Format: PDF Caterpillar CAT 320C, 320C L, 320C LN, 320C S Excavator Service Repair Manual 5475 Pages Description Caterpillar CAT 320C, 320C L, 320C LN, 320C S Excavator Service Repair Manual (BEA00001 and up) Excavator Model: 320C, 320C L, 320C LN, 320C S Serial Applicable: BEA00001 and up Language English