Cat 320C FM and 320D FM: forestry fronts, cab and circuits

320C FM: the forestry arrangement determines the job

Caterpillar offered the 320C FM as more than a log loader. The live-heel front suits loading and shovel logging; a Special Application reach front serves clearing and reforestation work. Processor packages could use a standard-gauge roadside arrangement or the high-wide/high-drawbar undercarriage for work at the stump.

Identify the installed front and undercarriage before comparing an auction machine with a roadbuilder or processor bearing the same model name.

Fine swing control was optional on the C. The standard high-drawbar final drives belonged to the high-wide undercarriage, with manually selected or automatic two-speed travel. Neither feature follows merely from seeing “FM” on the side panel.

Ask the seller to identify the swing-control equipment and final-drive arrangement for the intended loading routine.

The C also places its Electronic Technician test connection behind the cab. Its oil cooler swings horizontally for cleaning, and the right-side pump compartment gives access to the pilot filter. Those locations distinguish the inspection route from the later D's layout; do not assume a photograph of one generation identifies the service connection on the other.

320D FM: distinguish forestry and under/under log-loader equipment

A C6.4 ACERT with electronic engine management replaces the C's 3066 T. The June 2008 sheet pairs its headline flywheel figure with lower ISO and SAE net entries. Keep those standards separate when comparing engines.

General-forestry weights in that sheet assume an eighteen-inch riser and no bucket. The under/under log-loader weight instead assumes a forty-eight-inch riser and no grapple. A fitted grapple therefore cannot be treated as already included in every quoted machine weight.

The linkage cylinders differ too: the excavator front and heel-type loader are separate schedules, not interchangeable replacement-cylinder specifications.

Fine swing control is standard on this D. The Cat ET connection is inside the cab; its monitor checks engine oil, coolant and hydraulic-oil levels before startup. Confirm whether the optional reversing fan is fitted.

A clean outer screen does not establish that feature or reveal debris behind the cooling cores.

The forestry cab and heavy access doors also belong to the purpose-built package. A generic excavator with a forestry attachment should not be assumed to have the same guarding arrangement. Match the installed head and cab protection to the applicable operator documentation before use.