23 Belt drive parts are listed for the 2021 Freightliner 108SD, in 3 part types, covering all 3 engine options (6.7L L6 DIESEL Turbocharged, 7.7L L6 DIESEL Turbocharged and 8.9L L6 DIESEL Turbocharged). Each one has a brand, a manufacturer part number and notes that say where it fits.
The belt drive system on the 2021 Freightliner 108SD spins the accessories — serpentine and V-belts, tensioners, idlers and pulleys. All 23 listed parts are Belt (16 parts), Belt Tensioner (4 parts) and Idler Pulley (3 parts).
The 2021 Freightliner 108SD was sold with 3 engines. Every part on this page is engine-specific. Each part shows which engine(s) it fits.
4 brands supply belt drive parts for the 2021 Freightliner 108SD, led by GATES (10 parts), CONTINENTAL (7 parts) and DAYCO (4 parts), plus 1 more brand. Quality grades include Standard Replacement, Heavy Duty and Economy.
A "Popular" badge means the source catalog flagged the part as frequently chosen for the 2021 Freightliner 108SD. 4 parts have it, including GATES K080913HD (Belt) and GATES K080876HD (Belt). Each part number opens a page with every vehicle that part fits.
Belt
90-99" Length
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| GATES Fits: 6.7L L6 DIESEL Turbocharged | K080910 | 🇺🇸 US | Micro-V | View on Amazon |
Economy
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| CONTINENTAL Fits: 8.9L L6 DIESEL Turbocharged | 1035K8MK | 🇺🇸 US 🇨🇦 CA | Mileage MakerSerpentine | View on Amazon |
| CONTINENTAL Fits: 8.9L L6 DIESEL Turbocharged | 910K8MK | 🇺🇸 US 🇨🇦 CA | Mileage MakerSerpentine | View on Amazon |
Heavy Duty
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| GATES Popular Fits: 7.7L L6 DIESEL Turbocharged | K080913HD | 🇺🇸 US 🇨🇦 CA | Fleet Runner Heavy Duty Micro-V | View on Amazon |
| GATES Popular Fits: 7.7L L6 DIESEL Turbocharged | K080876HD | 🇺🇸 US 🇨🇦 CA | Fleet Runner Heavy Duty Micro-V | View on Amazon |
| GATES Popular Fits: 8.9L L6 DIESEL Turbocharged | K081040HD | 🇺🇸 US 🇨🇦 CA | Fleet Runner Heavy Duty Micro-V | View on Amazon |
| CONTINENTAL Fits: 8.9L L6 DIESEL Turbocharged | 4081035X | 🇺🇸 US 🇨🇦 CA | Extreme Duty Multi V-BeltSerpentine | View on Amazon |
| GATES Fits: 6.7L L6 DIESEL Turbocharged | K080910HD | 🇺🇸 US | Fleet Runner Heavy Duty Micro-V | View on Amazon |
Standard Replacement
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| GATES Popular Fits: 8.9L L6 DIESEL Turbocharged | K081040 | 🇺🇸 US 🇨🇦 CA | Micro-V | View on Amazon |
| CONTINENTAL Fits: 7.7L L6 DIESEL Turbocharged | 4080876 | 🇺🇸 US 🇨🇦 CA | Multi V-BeltSerpentine | View on Amazon |
| CONTINENTAL Fits: 8.9L L6 DIESEL Turbocharged | 4080910 | 🇺🇸 US 🇨🇦 CA | Multi V-BeltSerpentine | View on Amazon |
| DAYCO Fits: 6.7L L6 DIESEL Turbocharged | 5080910 | 🇺🇸 US | Serpentine | View on Amazon |
| DAYCO Fits: 7.7L L6 DIESEL Turbocharged | 5080915 | 🇺🇸 US 🇨🇦 CA | Serpentine | View on Amazon |
| DAYCO Fits: 7.7L L6 DIESEL Turbocharged | 5080875 | 🇺🇸 US 🇨🇦 CA | SerpentineGold Label Industrial Poly-Ribbed Belt | View on Amazon |
| GATES Fits: 7.7L L6 DIESEL Turbocharged | K080913 | 🇺🇸 US 🇨🇦 CA | Micro-V | View on Amazon |
| GATES Fits: 7.7L L6 DIESEL Turbocharged | K080876 | 🇺🇸 US 🇨🇦 CA | Micro-V | View on Amazon |
This table covers the serpentine and accessory belts that drive the front accessories. Typical signs include squeal on cold start, cracks across the ribs, or glazing on the back of the belt. A new belt on a worn tensioner will squeal within weeks — spin the idlers by hand while the belt is off.
16 Belt parts for the 2021 Freightliner 108SD come from 3 brands — GATES, CONTINENTAL and DAYCO. The "Popular" part is GATES K080913HD.
The 90-99" Length section lists 1 option from GATES — grouped under the catalog's "90-99" Length" designation — the notes column spells out what sets them apart. GATES K080910 is listed in this group.
The Economy section lists 2 options from CONTINENTAL — the catalog's value-priced group. CONTINENTAL 1035K8MK is listed in this group.
In the Heavy Duty grade, GATES and CONTINENTAL supply 5 parts: rated for severe service. A representative part number is GATES K080913HD.
In the Standard Replacement grade, GATES, DAYCO and CONTINENTAL supply 8 parts: built to original-equipment specification. A representative part number is GATES K081040.
Belt Tensioner
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| CONTINENTAL Fits: 8.9L L6 DIESEL Turbocharged | 49581 | 🇺🇸 US 🇨🇦 CA | Grooved Pulley | View on Amazon |
| DAYCO Fits: 8.9L L6 DIESEL Turbocharged | 89473 | 🇺🇸 US 🇨🇦 CA | Automatic TensionerHeavy Duty | View on Amazon |
| GATES Fits: 6.7L L6 DIESEL Turbocharged | 38702 | 🇺🇸 US | Fleet Runner | View on Amazon |
| LITENS Fits: 6.7L L6 DIESEL Turbocharged | 910588A | 🇺🇸 US | Fan | View on Amazon |
This table covers the automatic tensioners that hold belt tension. Typical signs include belt flutter, a chirp that returns after a new belt, or a damper that no longer holds the arm. Replace the tensioner with the belt at higher mileage; the labor overlaps almost entirely.
4 Belt Tensioner parts are listed for the 2021 Freightliner 108SD, from CONTINENTAL, DAYCO, GATES and 1 other brand.
This group includes CONTINENTAL 49581, DAYCO 89473 and GATES 38702 and the remaining parts above.
Idler Pulley
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| CONTINENTAL Fits: 8.9L L6 DIESEL Turbocharged | 49103 | 🇺🇸 US 🇨🇦 CA | Smooth | View on Amazon |
| GATES Fits: 8.9L L6 DIESEL Turbocharged | 36096 | 🇺🇸 US 🇨🇦 CA | Smooth or GroovedSmooth | View on Amazon |
| LITENS Fits: 8.9L L6 DIESEL Turbocharged | 900117A | 🇺🇸 US 🇨🇦 CA | Grooved or Smooth | View on Amazon |
This table covers the idler pulleys the belt wraps around. Typical signs include a chirp that follows engine speed, or a pulley that feels rough or has play. Replace a noisy idler with the belt — the labor is already paid for.
3 Idler Pulley parts for the 2021 Freightliner 108SD come from 3 brands — CONTINENTAL, GATES and LITENS.
This group includes CONTINENTAL 49103, GATES 36096 and LITENS 900117A.
Buying Belt Drive Parts for a 2021 Freightliner 108SD
On this vehicle, the belt drive system spins the accessories — serpentine and V-belts, tensioners, idlers and pulleys.
- Match the engine first. Every belt drive part here is 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, replace the tensioner and idler pulleys with any belt at higher mileage — the labor overlaps almost entirely.
- Cross-reference the manufacturer part number against your old part or a service-manual listing.
Start with the largest groups on this page: Belt and Belt Tensioner .
Frequently Asked Questions
How many belt drive parts fit the 2021 Freightliner 108SD?
Our catalog currently lists 23 belt drive parts for the 2021 Freightliner 108SD across 3 subcategories and 4 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 belt drive parts differ between 2021 Freightliner 108SD engines?
Yes. Every belt drive part on this page is engine-specific. Each row shows which engine(s) it fits — use the filter at the top to hide the rest. 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 belt drive problems on a 2021 Freightliner 108SD?
Common symptoms include squealing on cold start, a belt that shows cracking or glazing, or an accessory that slows under load. 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, replace the tensioner and idler pulleys with any belt at higher mileage — the labor overlaps almost entirely.
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 a new belt on a worn tensioner will squeal within weeks — check tensioner damping and idler bearings while the belt is off. The notes column carries position and trim qualifiers where they apply.
Other Parts for the 2021 Freightliner 108SD
Belt Drive Parts for Other Freightliner 108SD Years
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