The 2021 Freightliner M2 has 53 belt drive parts with verified fitment on this page — 3 part types and 6 brands, covering all 8 engine options (12.8L L6 DIESEL Turbocharged, 4.8L L4 DIESEL Turbocharged, 5.1L L4 DIESEL Turbocharged, 6.7L L6 DIESEL Turbocharged and more). Each part includes a manufacturer part number and application notes.
The belt drive system on the 2021 Freightliner M2 spins the accessories — serpentine and V-belts, tensioners, idlers and pulleys. All 53 listed parts are Belt (27 parts), Belt Tensioner (14 parts) and Idler Pulley (12 parts).
The 2021 Freightliner M2 was sold with 8 engines. Every part on this page is engine-specific. Each part shows which engine(s) it fits.
The most listed brands for 2021 Freightliner M2 belt drive parts are GATES (21 parts), DAYCO (11 parts) and CONTINENTAL (10 parts), plus 3 more brands. Quality grades include Standard Replacement, Heavy Duty and Economy.
7 parts on this 2021 Freightliner M2 page carry a "Popular" badge — the source catalog's flag for options frequently chosen for this vehicle — including GATES K100643HD (Belt) and GATES 38667 (Belt Tensioner). Click any part number to see every vehicle that part fits.
Belt
Economy
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| CONTINENTAL Fits: 8.9L L6 DIESEL Turbocharged, 8.9L L6 Turbocharged | 855K8MK | 🇺🇸 US 🇨🇦 CA | Mileage MakerSerpentine | View on Amazon |
| DAYCO Fits: 6.7L L6 DIESEL Turbocharged | 5080810DR | 🇺🇸 US 🇨🇦 CA | Drive Rite®Serpentine | View on Amazon |
Heavy Duty
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| GATES Popular Fits: 12.8L L6 DIESEL Turbocharged | K100643HD | 🇺🇸 US 🇨🇦 CA | Fleet Runner Heavy Duty Micro-V | View on Amazon |
| GATES Popular Fits: 5.1L L4 DIESEL Turbocharged, 7.7L L6 DIESEL Turbocharged | K080913HD | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | Fleet Runner Heavy Duty Micro-V | View on Amazon |
| GATES Popular Fits: 5.1L L4 DIESEL Turbocharged, 7.7L L6 DIESEL Turbocharged | K080708HD | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | Fleet Runner Heavy Duty Micro-V | View on Amazon |
| GATES Popular Fits: 8.9L L6 Turbocharged | K080825HD | 🇺🇸 US 🇨🇦 CA | Fleet Runner Heavy Duty Micro-V | View on Amazon |
| CONTINENTAL Fits: 12.8L L6 DIESEL Turbocharged | 4100642FX | 🇺🇸 US 🇨🇦 CA | Extreme Duty Multi V-BeltSerpentine | View on Amazon |
| CONTINENTAL Fits: 12.8L L6 DIESEL Turbocharged | 4081051X | 🇺🇸 US 🇨🇦 CA | Extreme Duty Multi V-BeltSerpentine | View on Amazon |
| CONTINENTAL Fits: 8.9L L6 DIESEL Turbocharged, 8.9L L6 Turbocharged | 4080855X | 🇺🇸 US 🇨🇦 CA | Extreme Duty Multi V-BeltSerpentine | View on Amazon |
| GATES Fits: 12.8L L6 DIESEL Turbocharged | K081051HD | 🇺🇸 US 🇨🇦 CA | Fleet Runner Heavy Duty Micro-V | View on Amazon |
| GATES Fits: 6.7L L6 DIESEL Turbocharged | K080808HD | 🇺🇸 US 🇨🇦 CA | Fleet Runner Heavy Duty Micro-V | View on Amazon |
| GATES Fits: 7.2L L6 DIESEL Turbocharged | K080820HD | 🇲🇽 MX | Fleet Runner Heavy Duty Micro-V | View on Amazon |
| GATES Fits: 8.9L L6 DIESEL Turbocharged | K080845HD | 🇺🇸 US 🇨🇦 CA | Fleet Runner Heavy Duty Micro-V | View on Amazon |
Standard Replacement
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| DAYCO Popular Fits: 7.7L L6 DIESEL Turbocharged | 5080705 | 🇺🇸 US 🇨🇦 CA | Serpentine | View on Amazon |
| ACDELCO Fits: 5.1L L4 DIESEL Turbocharged, 7.7L L6 DIESEL Turbocharged | 8K708 | 🇺🇸 US 🇨🇦 CA | Professional / GoldSerpentine | View on Amazon |
| ACDELCO Fits: 8.9L L6 Turbocharged | 8K825 | 🇺🇸 US 🇨🇦 CA | Professional / GoldSerpentine | View on Amazon |
| CONTINENTAL Fits: 5.1L L4 DIESEL Turbocharged, 7.7L L6 DIESEL Turbocharged | 4080708 | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | Multi V-BeltSerpentine | View on Amazon |
| DAYCO Fits: 5.1L L4 DIESEL Turbocharged, 7.7L L6 DIESEL Turbocharged | 5080915 | 🇺🇸 US 🇨🇦 CA | Serpentine | View on Amazon |
| DAYCO Fits: 5.1L L4 DIESEL Turbocharged | 5080710 | 🇺🇸 US 🇨🇦 CA | SerpentineGold Label Industrial Poly-Ribbed Belt | View on Amazon |
| DAYCO Fits: 6.7L L6 DIESEL Turbocharged | 5080810 | 🇺🇸 US 🇨🇦 CA | Serpentine | View on Amazon |
| DAYCO Fits: 8.9L L6 DIESEL Turbocharged | 5080845 | 🇺🇸 US 🇨🇦 CA | Serpentine | View on Amazon |
| GATES Fits: 12.8L L6 DIESEL Turbocharged | K081051 | 🇺🇸 US 🇨🇦 CA | Micro-V | View on Amazon |
| GATES Fits: 5.1L L4 DIESEL Turbocharged, 7.7L L6 DIESEL Turbocharged | K080913 | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | Micro-V | View on Amazon |
| GATES Fits: 5.1L L4 DIESEL Turbocharged, 7.7L L6 DIESEL Turbocharged | K080708 | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | Micro-V | View on Amazon |
| GATES Fits: 7.2L L6 DIESEL Turbocharged | K080820 | 🇲🇽 MX | Micro-V | View on Amazon |
| GATES Fits: 8.9L L6 Turbocharged | K080825 | 🇺🇸 US 🇨🇦 CA | Micro-V | View on Amazon |
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| GATES Fits: 6.7L L6 DIESEL Turbocharged | K080808 | 🇺🇸 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.
27 Belt parts are listed for the 2021 Freightliner M2, from GATES, DAYCO, CONTINENTAL and 1 other brand. GATES K100643HD carries the "Popular" badge. Grades run from Economy through Standard Replacement; Standard Replacement is the most populated section, led by DAYCO, GATES, ACDELCO and 1 other brand.
Belt Tensioner
Economy
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| SKP Fits: 12.8L L6 DIESEL Turbocharged | SK38667 | 🇺🇸 US 🇨🇦 CA | View on Amazon |
Standard Replacement
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| GATES Popular Fits: 12.8L L6 DIESEL Turbocharged | 38667 | 🇺🇸 US 🇨🇦 CA | Fleet Runner | View on Amazon |
| CONTINENTAL Fits: 12.8L L6 DIESEL Turbocharged | 49603 | 🇺🇸 US 🇨🇦 CA | Multi-V | View on Amazon |
| DAYCO Fits: 12.8L L6 DIESEL Turbocharged | 89947 | 🇺🇸 US 🇨🇦 CA | Replaces 89498 and 89498A | View on Amazon |
| LITENS Fits: 12.8L L6 DIESEL Turbocharged | 910585A | 🇺🇸 US 🇨🇦 CA | View on Amazon |
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| CONTINENTAL Fits: 8.9L L6 DIESEL Turbocharged, 8.9L L6 Turbocharged | 49581 | 🇺🇸 US 🇨🇦 CA | Grooved Pulley | View on Amazon |
| DAYCO Fits: 6.7L L6 DIESEL Turbocharged | 89930 | 🇺🇸 US 🇨🇦 CA | View on Amazon | |
| DAYCO Fits: 8.9L L6 DIESEL Turbocharged, 8.9L L6 Turbocharged | 89473 | 🇺🇸 US 🇨🇦 CA | Automatic TensionerHeavy Duty | View on Amazon |
| GATES Fits: 6.7L L6 DIESEL Turbocharged | 38702 | 🇺🇸 US 🇨🇦 CA | Fleet Runner | View on Amazon |
| GATES Fits: 7.2L L6 DIESEL Turbocharged | 38567 | 🇲🇽 MX | Fleet Runner | View on Amazon |
| GATES Fits: 8.9L L6 DIESEL Turbocharged | 38627 | 🇺🇸 US 🇨🇦 CA | Fleet Runner | View on Amazon |
| LITENS Fits: 6.7L L6 DIESEL Turbocharged | 910588A | 🇺🇸 US 🇨🇦 CA | View on Amazon | |
| LITENS Fits: 7.2L L6 DIESEL Turbocharged | 910552A | 🇲🇽 MX | View on Amazon | |
| LITENS Fits: 8.9L L6 DIESEL Turbocharged | 910567A | 🇺🇸 US 🇨🇦 CA | 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.
14 Belt Tensioner parts for the 2021 Freightliner M2 come from 5 brands — GATES, LITENS, DAYCO and 2 other brands. The "Popular" part is GATES 38667.
The Economy section lists 1 option from SKP — the catalog's value-priced group. SKP SK38667 is listed in this group.
In the Standard Replacement grade, GATES, CONTINENTAL, DAYCO and 1 other brand supply 4 parts: built to original-equipment specification. A representative part number is GATES 38667.
9 further parts sit outside the graded sections, with the same engine-level match.
Idler Pulley
Economy
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| SKP Fits: 8.9L L6 DIESEL Turbocharged | SK89106 | 🇺🇸 US 🇨🇦 CA | Smooth | View on Amazon |
Standard Replacement
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| DAYCO Popular Fits: 8.9L L6 DIESEL Turbocharged | 89106 | 🇺🇸 US 🇨🇦 CA | Grooved or Smooth | View on Amazon |
| 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 |
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| CONTINENTAL Fits: 12.8L L6 DIESEL Turbocharged | 50073 | 🇺🇸 US 🇨🇦 CA | Smooth | View on Amazon |
| CONTINENTAL Fits: 8.9L L6 Turbocharged | 49103 | 🇺🇸 US 🇨🇦 CA | Smooth | View on Amazon |
| DAYCO Fits: 12.8L L6 DIESEL Turbocharged | 89124 | 🇺🇸 US 🇨🇦 CA | Smooth | View on Amazon |
| GATES Fits: 12.8L L6 DIESEL Turbocharged | 36742 | 🇺🇸 US 🇨🇦 CA | Smooth | View on Amazon |
| GATES Fits: 8.9L L6 Turbocharged | 36096 | 🇺🇸 US 🇨🇦 CA | Smooth or GroovedSmooth | View on Amazon |
| LITENS Fits: 12.8L L6 DIESEL Turbocharged | 900657A | 🇺🇸 US 🇨🇦 CA | Smooth | View on Amazon |
| LITENS Fits: 8.9L L6 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.
12 Idler Pulley parts are listed for the 2021 Freightliner M2, from CONTINENTAL, GATES, LITENS and 2 other brands. DAYCO 89106 carries the "Popular" badge.
Economy: 1 part, from SKP. A representative part number is SKP SK89106.
The Standard Replacement section: 4 options from DAYCO, CONTINENTAL, GATES and 1 other brand. DAYCO 89106 is listed in this group.
7 ungrouped parts are not assigned to a grade, with the same engine-level match.
Buying Belt Drive Parts for a 2021 Freightliner M2
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 M2?
Our catalog currently lists 53 belt drive parts for the 2021 Freightliner M2 across 3 subcategories and 6 brands, covering all 8 engine options (12.8L L6 DIESEL Turbocharged, 4.8L L4 DIESEL Turbocharged, 5.1L L4 DIESEL Turbocharged, 6.7L L6 DIESEL Turbocharged and more). Each part is matched to the engine(s) it fits.
Do belt drive parts differ between 2021 Freightliner M2 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 M2?
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 M2 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 M2?
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 M2
Belt Drive Parts for Other Freightliner M2 Years
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