This page lists 16 electrical parts for the 2021 Freightliner 108SD, across 3 part types, covering all 3 engine options (6.7L L6 DIESEL Turbocharged, 7.7L L6 DIESEL Turbocharged and 8.9L L6 DIESEL Turbocharged). Every part shows its brand, manufacturer part number and fitment notes.
The electrical system on the 2021 Freightliner 108SD covers charging, starting and the sensors and modules the vehicle relies on, from alternator and starter to oxygen sensors. All 16 listed parts are Alternator / Generator (7 parts), Battery (5 parts) and Starter Motor (4 parts).
The 2021 Freightliner 108SD was sold with 3 engines. 3 parts fit every engine; the other 13 are engine-specific. Each part shows which engine(s) it fits.
6 brands supply electrical parts for the 2021 Freightliner 108SD, led by WAI GLOBAL (9 parts), BOSCH (2 parts) and FVP (2 parts), plus 3 more brands.
A "Popular" badge means the source catalog flagged the part as frequently chosen for the 2021 Freightliner 108SD. 3 parts have it, including WAI GLOBAL 8614N (Alternator / Generator) and FVP P31TAGM (Battery). Each part number opens a page with every vehicle that part fits.
Alternator / Generator
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| WAI GLOBAL Popular Fits: 6.7L L6 DIESEL Turbocharged, 7.7L L6 DIESEL Turbocharged | 8614N | 🇺🇸 US 🇨🇦 CA | Does Not Include Pulley | View on Amazon |
| WAI GLOBAL Popular Fits: 6.7L L6 DIESEL Turbocharged, 7.7L L6 DIESEL Turbocharged | 8681N | 🇺🇸 US 🇨🇦 CA | Does Not Include Pulley | View on Amazon |
| BOSCH Fits: 6.7L L6 DIESEL Turbocharged, 8.9L L6 DIESEL Turbocharged | AL9961LH | 🇺🇸 US 🇨🇦 CA | Does Not Include Pulley | View on Amazon |
| BOSCH Fits: 6.7L L6 DIESEL Turbocharged, 8.9L L6 DIESEL Turbocharged | AL9962SB | 🇺🇸 US 🇨🇦 CA | Does Not Include Pulley | View on Amazon |
| WAI GLOBAL Fits: 6.7L L6 DIESEL Turbocharged, 7.7L L6 DIESEL Turbocharged | 8741N | 🇺🇸 US 🇨🇦 CA | Does Not Include Pulley | View on Amazon |
| WAI GLOBAL Fits: 6.7L L6 DIESEL Turbocharged, 7.7L L6 DIESEL Turbocharged | 8912N | 🇺🇸 US 🇨🇦 CA | Does Not Include Pulley | View on Amazon |
| WAI GLOBAL Fits: 7.7L L6 DIESEL Turbocharged | 8719N | 🇺🇸 US 🇨🇦 CA | Does Not Include Pulley | View on Amazon |
This table covers the alternators that charge the battery and run the electrical load. Typical signs include dim lights at idle, a battery lamp, or a growl from the charging pulley. Load-test the battery and inspect the belt and grounds — a bad ground mimics a failed alternator.
7 Alternator / Generator parts for the 2021 Freightliner 108SD come from 2 brands — WAI GLOBAL and BOSCH. The "Popular" part is WAI GLOBAL 8614N.
This group includes WAI GLOBAL 8614N, WAI GLOBAL 8681N and BOSCH AL9961LH and the remaining parts above.
Battery
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| FVP Popular Fits: all 2021 108SD engines | P31TAGM | 🇺🇸 US 🇨🇦 CA | Platinum AGMBCI Group: 31T | View on Amazon |
| ACDELCO Fits: 6.7L L6 DIESEL Turbocharged, 7.7L L6 DIESEL Turbocharged | 31XAGMT | 🇺🇸 US 🇨🇦 CA | AGMBCI Group: 31 | View on Amazon |
| EXIDE Fits: 6.7L L6 DIESEL Turbocharged, 7.7L L6 DIESEL Turbocharged | XRF31D | 🇺🇸 US 🇨🇦 CA | RoadforceBCI Group 31 | View on Amazon |
| FVP Fits: all 2021 108SD engines | PC318STAGM | 🇺🇸 US 🇨🇦 CA | Platinum AGM | View on Amazon |
| MOTORCRAFT Fits: all 2021 108SD engines | BHAGM31 | 🇺🇸 US 🇨🇦 CA | Fleettough/ExtraBCI Group: 31 | View on Amazon |
This table covers the batteries listed by group size and specification. Typical signs include slow cranking, a battery lamp, or a no-start after the vehicle sat overnight. Confirm group size and terminal layout in the notes. Clean the posts and the ground before condemning the battery.
5 Battery parts are listed for the 2021 Freightliner 108SD, from FVP, ACDELCO, EXIDE and 1 other brand. FVP P31TAGM carries the "Popular" badge. 3 parts fit every engine; the other 2 are engine-specific.
Listed part numbers: FVP P31TAGM, ACDELCO 31XAGMT and EXIDE XRF31D, plus the other parts above.
Starter Motor
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| WAI GLOBAL Fits: 6.7L L6 DIESEL Turbocharged | 6809N | 🇺🇸 US | Optional Replacement Delco 38MTwith Integral Magnetic Switch | View on Amazon |
| WAI GLOBAL Fits: 6.7L L6 DIESEL Turbocharged | 6963N | 🇺🇸 US | View on Amazon | |
| WAI GLOBAL Fits: 6.7L L6 DIESEL Turbocharged | 34029N | 🇺🇸 US | without Ground Stud | View on Amazon |
| WAI GLOBAL Fits: 7.7L L6 DIESEL Turbocharged | 34042N | 🇺🇸 US 🇨🇦 CA | MOD 3.0 | View on Amazon |
This table covers the starter motors that crank the engine. Typical signs include no motion, a squeal, or a motor that only runs on one speed. Confirm power, ground and the control module before replacing the motor.
4 Starter Motor parts for the 2021 Freightliner 108SD come from WAI GLOBAL.
Listed part numbers: WAI GLOBAL 6809N, WAI GLOBAL 6963N and WAI GLOBAL 34029N, plus the other parts above.
Buying Electrical Parts for a 2021 Freightliner 108SD
On this vehicle, the electrical system covers charging, starting and the sensors and modules the vehicle relies on, from alternator and starter to oxygen sensors.
- Match the engine first. Some electrical parts fit every engine; others are engine-specific. Each row shows which engine(s) it fits.
- Read the notes on each row for position, trim and spec qualifiers before you order.
- Where labor overlaps, clean or renew the battery terminals and grounds with any charging-system repair.
- Cross-reference the manufacturer part number against your old part or a service-manual listing.
Start with the largest groups on this page: Alternator / Generator and Battery .
Frequently Asked Questions
How many electrical parts fit the 2021 Freightliner 108SD?
Our catalog currently lists 16 electrical parts for the 2021 Freightliner 108SD across 3 subcategories and 6 brands, covering all 3 engine options (6.7L L6 DIESEL Turbocharged, 7.7L L6 DIESEL Turbocharged and 8.9L L6 DIESEL Turbocharged). Each part is matched to the engine(s) it fits.
Do electrical parts differ between 2021 Freightliner 108SD engines?
Some do. 3 parts fit every engine; the other 13 are engine-specific. Each row (and the filter at the top) shows which. If you're unsure which engine you have, check the emissions label under the hood or the 8th character of your VIN.
What are the signs of electrical problems on a 2021 Freightliner 108SD?
Common symptoms include slow cranking on cold mornings, a battery light that flickers, dim lights at idle, or a check-engine code pointing at a sensor circuit. If you notice any of these, identify the affected subcategory above and cross-reference the part numbers listed.
What should I replace at the same time?
Where labor overlaps, clean or renew the battery terminals and grounds with any charging-system repair.
What do the market flags (US, CA, MX) on each part mean?
They show the market for which the manufacturer published application data for that part — where the vehicle was first sold, not where the part was made. If your 2021 Freightliner 108SD was originally sold in the US, the safest choice is a part marked for the US market.
How do I make sure a part fits my 2021 Freightliner 108SD?
First match the engine — each row shows which engine(s) the part fits. Then test before replacing — a failed alternator and a bad ground can look identical, and sensors are frequently condemned for wiring faults. The notes column carries position and trim qualifiers where they apply.
Other Parts for the 2021 Freightliner 108SD
Electrical Parts for Other Freightliner 108SD Years
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