OEX Alternator 12V 135A Delco 33SI Style DXA9121

The OEX Alternator DXA9121 is a new 12V, 135A unit in Delco 33SI style, supplied as an alternator for rotating electrical applications. It uses an internal regulator, twin leg mounting, a 22mm shaft diameter and a 198mm mount centre to centre measurement, so the physical pattern needs to match the vehicle or equipment already being repaired.

This unit is listed with an inside mounting legs measurement of 101mm, a pivot hole diameter of 13mm and an adjusting hole diameter of 1/2 UNC. Those dimensions matter when checking bracket alignment and mounting hardware, especially where the original alternator is a Delco 33SI style unit and the fit is determined by the exact mounting points rather than appearance alone.

OEX describes this product as being sourced from leading original equipment manufacturers and aftermarket suppliers, with ISO9001 certified factories used for engineering, testing and quality control procedures. It carries a 3 year passenger / 1 year commercial warranty, and the alternator is supplied new at 12.36kg per unit.

Key Features

• 12V alternator with 135A output
• Delco 33SI style
• New unit, not remanufactured
• Internal regulator
• Twin leg alternator mount
• 22mm shaft diameter

Specifications

• Part No.: DXA9121
• Brand: OEX
• Product type: Alternator
• Voltage: 12V
• Power rating: 135A
• Series: 33SI
• Suits unit make: Delco
• Regulator type: Internal

Known application groups supplied for this alternator

• CASE 9150
• CASE IH 9380
• CATERPILLAR 12H
• CATERPILLAR 3126
• CHAMPION 710A
• CHAMPION 720A SERIES
• CUMMINS NTC-855
• FORD 900-SERIES

Application and Buying Notes

Before ordering, check the part number DXA9121 and compare the mounting pattern carefully against the existing alternator. The key measurements here are the 198mm mount centre to centre, 101mm inside mounting legs, 13mm pivot hole diameter, 1/2 UNC adjusting hole diameter and 22mm shaft diameter. If any of those differ from the unit already fitted, the alternator may not align correctly even if it is a Delco 33SI style unit.

The 135A output and 12V rating are important when matching charging system requirements. This alternator is listed as an internal regulator type, so the vehicle or machine setup needs to suit an internally regulated alternator rather than an external regulator arrangement. That is especially important on mixed fleet repairs where similar-looking alternators can have different regulation and mounting setups.

This is a new alternator and not a remanufactured unit, with a listed weight of 12.36kg. If the replacement is being chosen for a commercial application, the warranty is 1 year commercial; for passenger use it is 3 years. Those warranty terms do not replace the need to confirm fitment first, but they do provide a clear service expectation once the correct application has been selected.

The supplied application groups cover a wide range of heavy vehicle and equipment platforms, including CASE, CATERPILLAR, CHAMPION, CUMMINS, FORD, FREIGHTLINER, INTERNATIONAL, KENWORTH, MACK, NEW HOLLAND, STERLING TRUCKS, VERSATILE and WESTERN STAR. Because the application list spans several makes and series, it is sensible to verify the exact installation points and not rely on make name alone when comparing against the original alternator.

Before supply, the safest approach is to confirm the original unit details against the listed part number, voltage, output rating, mounting arrangement, and pulley configuration. That checking process is standard practice in the parts trade because visually similar units can still differ in service-critical ways.

For workshop, fleet, and equipment applications, accurate identification of part number DXA9121 helps avoid unnecessary freight, additional labour, and vehicle or machine downtime. Where the application is not straightforward, the original unit, OEM reference, or workshop records should be used as the primary confirmation point.

Relevant published details for this unit include Type ALTERNATOR, Unit of Measure EACH, Warranty 3yr Passenger 1yr Commercial, Inside Mounting Legs 101mm, Power Rating (Amp) 135, Series 33SI, Suits Unit Make Delco, Note Brushless, Mount Cnt to Cnt 198mm, Shaft Dimension 22.

Additional published details for cross-checking include Product Group 2 ALTERNATORS, Part No. DXA9121, Brand OEX, Description OEX Alternator 12V 135A Delco 33SI Style, Adjusting Hole Diameter 1/2 UNC, Pivot Hole Diameter 13, Regulator Type Internal, Shaft Diameter 22mm, Voltage 12.

OEX Alternator 12V 135A Delco 33SI Style. Part number DXA9121 should be checked first. Listed voltage is 12. Listed output rating is 135. These details form the core reference points used by parts interpreters when confirming the correct replacement.

Mount style is Twin Leg. Regulator type is Internal. Those physical and electrical details should line up with the original unit before the replacement is approved for fitment.

For part number DXA9121, the normal identification sequence is part number, electrical rating, mounting arrangement, connector or terminal style, and pulley or drive details. Using those checkpoints helps confirm that the listed unit matches the service requirement rather than only looking similar.

For a alternator in workshop, fleet, trade, agricultural, or construction service, the listed voltage 12 and output 135 should be checked carefully. Incorrect selection can affect installation time, return freight, and equipment availability.

Available application references include CASE 9150, CASE IH, CASE IH 9380, CASE IH 9380 1999, CATERPILLAR 12H, CATERPILLAR 12H 2001. Even with application listings, final confirmation should still be based on the exact unit being replaced and the service requirements of the vehicle or machine.

Compatibility note: Confirm compatibility using part number DXA9121, the Delco 33SI style designation, and the mounting and shaft measurements before ordering. Vehicle and equipment application can vary even within the same make or series.

FAQ

What is the part number for this alternator?

The part number is DXA9121.

What voltage and output does this alternator have?

It is a 12V alternator with a 135A power rating.

Is this a new or remanufactured unit?

It is listed as new, not remanufactured.

What type of regulator does it use?

It uses an internal regulator.

What mounting and shaft measurements should be checked?

Check the twin leg mount, 198mm mount centre to centre, 101mm inside mounting legs, 13mm pivot hole diameter, 1/2 UNC adjusting hole diameter and 22mm shaft diameter.

What warranty is listed?

The warranty is 3 years for passenger use and 1 year for commercial use.