320D and 320D2 alternators are different assemblies
The 320D KGF / GDP alternator entry is 212-8561; the 320D2 DNS / ZCS / RAR entry is 344-5081. Their rated output and mounting form differ.
| Number | Machine entry | Rating | Mount / construction |
|---|---|---|---|
| 212-8561 | 320D KGF / GDP | 28 V / 50 A | Hinge, brush type,4 poles |
| 344-5081 | 320D2 DNS / ZCS / RAR | 24 V / 115 A | Pad, brush type,12 poles |
| 20R-0958 | Reman alternative to 344-5081 | 24 V / 115 A | Pad-mount Cat Reman |
Read charging voltage and nominal system voltage separately
A nominal 24-volt machine system needs a charging assembly designed for that installation. The 212-8561 product specification states a 28-volt output rating, while 344-5081 states 24 volts. The installed number, rated current and mounting remain part of the selection; voltage by itself does not make these two alternators interchangeable.
3T-5760 is a 12-volt battery unit
The 3T-5760 wet battery uses SAE posts and BCI Group31/30H sizing. It has 750 CCA, 100 Ah at the 20-hour rate and 165 minutes reserve capacity. A machine battery bank can use more than one battery, so the order states the unit voltage and battery-bank quantity separately.
| Field | Value |
|---|---|
| Unit voltage | 12 V |
| Cold-cranking current | 750 CCA |
| Capacity | 100 Ah at20-hour rate |
| Reserve capacity | 165 min |
| Size | 13 ×6.8 ×9.5 in |
| Terminals | SAE posts |
| Construction | Accessible wet battery |
Starter, alternator and harness lines need different details
A starter purchase includes its pinion, nose mounting and electrical terminals. An alternator includes its mount, pulley offset and regulator/connector. A harness purchase uses the controller-side and component-side plugs, connector keying and wire route.
| Item | Fit / function fields |
|---|---|
| Starter | Voltage, kW, pinion tooth count, nose and flange |
| Alternator | Voltage, A, mount, pulley and connections |
| Battery | Voltage, CCA, case size, terminal form and arrangement |
| Wiring harness | Full part number, plugs, keying, branch layout |
Separate new and remanufactured offers
The Cat Reman 20R-0958 is a distinct purchase identity beside new 344-5081. The quote should list the selected condition, supplied pulley/regulator and any core-return arrangement. Belt numbers and electrical connectors can be added as separate repair items.
Buying questions
Are212-8561 and 344-5081 interchangeable alternators?
They have different output ratings and mounting forms. 212-8561 is28 V / 50 A hinge; 344-5081 is24 V / 115 Apad. Compare the installed number and physical connection.
Does3T-5760 identify a24V battery?
It is a12 V battery unit. The fitted machine battery bank determines how many units and how they are connected.
What does CCA measure?
Cold-cranking amperes describe starting-current capacity at low temperature. Amp-hour capacity and reserve minutes describe separate battery performance fields.
Can a starter and alternator be quoted as one engine repair?
Yes. Give each its full number and quantity, with the machine prefix and engine identity. They remain separate components on the packing list.