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Peterbilt 357/378 Parts

Find the best Peterbilt 378 aftermarket parts in the business here at 4 State. The Peterbilt 378 semi truck represents all of the characteristics of the Peterbilt brand, and was a popular model with similar features to the Peterbilt 379. Pete truck models are a brand of choice for experienced truckers who need dependable semi trucks. 4 State Trucks has all the semi truck parts and accessories you need to make your Pete 378 stand out to showcase your unique personality. Whether you need aftermarket bumpers, exhaust, or fuel tanks, we've got you covered. Hit the open road in style and comfort with the best custom gear for your Peterbilt heavy duty truck or 18 wheeler.
  • Product
  • Qty in Cart
  • Quantity
  • Price
  • Subtotal
  • 21 Inch Stainless Steel Blank Top Flap Accent Trim

    21 Inch Stainless Steel Blank Top Flap Accent Trim

    ROADWORKS

    $37.33
    21 Inch Blank Top Flap Accent TrimAchieve durable protection and a refined look with the 21 Inch Stainless Steel Blank Top Flap Accent Trim. Crafted from premium stainless steel and measuring 21...
    09-05070622
    SKU:
    09-05070622
    Location:
    Made In USA
    Material Options:
    Stainless Steel
    Product Type:
    Mud Flaps
    Width Options:
    21 Inch
    Make:
    Universal Items
    $37.33
    Qty in Cart: 0
    Price:
    $37.33
    Subtotal:
  • 19 Inch Stainless Steel Blank Top Flap Accent Trim

    19 Inch Stainless Steel Blank Top Flap Accent Trim

    ROADWORKS

    $36.29
    19 Inch Blank Top Flap Accent TrimUpgrade your truck's mud flaps with the 19 Inch Stainless Steel Blank Top Flap Accent Trim, crafted from premium stainless steel for exceptional durability and...
    09-05070621
    SKU:
    09-05070621
    Location:
    Made In USA
    Material Options:
    Stainless Steel
    Product Type:
    Mud Flaps
    Width Options:
    19 Inch
    Make:
    Universal Items
    $36.29
    Qty in Cart: 0
    Price:
    $36.29
    Subtotal:
  • Stainless Steel “I Love My Kids” Flap Weights

    Stainless Steel “I Love My Kids” Flap Weights

    ROADWORKS

    $71.99
    24 Inch "I Love My Kids" Flap WeightsExpress your love and personalize your truck with the Stainless Steel "I Love My Kids" Flap Weights, designed for durability and style. Made from high-quality...
    09-05070605
    SKU:
    09-05070605
    Location:
    Made In USA
    Material Options:
    Stainless Steel
    Product Type:
    Mud Flaps
    Width Options:
    24 Inch
    Make:
    Universal Items
    $71.99
    Qty in Cart: 0
    Price:
    $71.99
    Subtotal:
  • 15 Inch Stainless Steel Blank Top Flap Accent Trim

    15 Inch Stainless Steel Blank Top Flap Accent Trim

    ROADWORKS

    $33.18
    15 Inch Blank Top Flap Accent TrimStrengthen your mud flaps and elevate your truck's look with the 15 Inch Stainless Steel Blank Top Flap Accent Trim. Made from premium stainless steel, each 15-inch...
    09-05070620
    SKU:
    09-05070620
    Location:
    Made In USA
    Material Options:
    Stainless Steel
    Product Type:
    Mud Flaps
    Width Options:
    15 Inch
    Make:
    Universal Items
    $33.18
    Qty in Cart: 0
    Price:
    $33.18
    Subtotal:
  • 1/4 X 1-1/2 Inch Brass Long Nipple Replaces 3327X4, 215PNL415

    1/4 X 1-1/2 Inch Brass Long Nipple Replaces 3327X4, 215PNL415

    AUTOMANN USA

    $2.54
    1/4 X 1-1/2 Inch Brass Long NippleBuild dependable connections with the 1/4 X 1-1/2 Inch Brass Long Nipple, a premium brass fitting designed for leak-free performance. With male NPT threads on both...
    09-05040130
    SKU:
    09-05040130
    Diameter Options:
    1/4 Inch
    Length Options:
    1 1/2 Inch
    Material Options:
    Brass
    Product Type:
    Air, Electrical, & Safety
    Make:
    Universal Items
    $2.54
    Qty in Cart: 0
    Price:
    $2.54
    Subtotal:
  • 1/2 X 1-1/2 Inch Brass Long Nipple Replaces 215PNL815

    1/2 X 1-1/2 Inch Brass Long Nipple Replaces 215PNL815

    AUTOMANN USA

    $3.80
    1/2 X 1-1/2 Inch Brass Long NippleDepend on the 1/2 X 1-1/2 Inch Brass Long Nipple for strong, leak-resistant pipe connections. Crafted from solid brass with male NPT threads on both ends, this...
    09-05040117
    SKU:
    09-05040117
    Diameter Options:
    1/2 Inch
    Length Options:
    1 1/2 Inch
    Material Options:
    Brass
    Product Type:
    Air, Electrical, & Safety
    Make:
    Universal Items
    $3.80
    Qty in Cart: 0
    Price:
    $3.80
    Subtotal:
  • 3/16 Inch Barb X 1/8 Inch Pipe Brass Hose Fitting Replaces 10503B102

    3/16 Inch Barb X 1/8 Inch Pipe Brass Hose Fitting Replaces 10503B102

    AUTOMANN USA

    $0.91
    3/16 Inch Barb X 1/8 Inch Pipe Hose Fitting* High Quality Hose Fitting* Hose Barb To Male NPT Connection* Use With 3/16" Push-On Hose* Made Of Brass* Barb Hose End: 3/16 Inch Inner Diameter* Male NPT...
    09-05040116
    SKU:
    09-05040116
    Material Options:
    Brass
    Product Type:
    Air, Electrical, & Safety
    Make:
    Universal Items
    $0.91
    Qty in Cart: 0
    Price:
    $0.91
    Subtotal:
  • 3/16 Inch Barb X 1/4 Inch Pipe Brass Hose Fitting Replaces 10503B104

    3/16 Inch Barb X 1/4 Inch Pipe Brass Hose Fitting Replaces 10503B104

    AUTOMANN USA

    $1.81
    3/16 Inch Barb X 1/4 Inch Pipe Hose Fitting* High Quality Hose Fitting* Hose Barb To Male NPT Connection* Use With 3/8" Push-On Hose* Made Of Brass* Barb Hose End: 3/8 Inch Inner Diameter* Male NPT...
    09-05040115
    SKU:
    09-05040115
    Material Options:
    Brass
    Product Type:
    Air, Electrical, & Safety
    Make:
    Universal Items
    $1.81
    Qty in Cart: 0
    Price:
    $1.81
    Subtotal:
  • 3/8 X 1-1/2 Inch Brass Long Nipple Replaces 3327X6, 215PNL615

    3/8 X 1-1/2 Inch Brass Long Nipple Replaces 3327X6, 215PNL615

    AUTOMANN USA

    $3.81
    3/8 X 1-1/2 Inch Brass Long NippleAchieve reliable and leak-free connections with the 3/8 X 1-1/2 Inch Brass Long Nipple, a high-quality fitting built for durability and professional performance...
    09-05040119
    SKU:
    09-05040119
    Diameter Options:
    3/8 Inch
    Length Options:
    1 1/2 Inch
    Material Options:
    Brass
    Product Type:
    Air, Electrical, & Safety
    Make:
    Universal Items
    $3.81
    Qty in Cart: 0
    Price:
    $3.81
    Subtotal:
  • 3/8 Inch Barb X 3/8 Inch Pipe Brass Hose Fitting Replaces 10506B106, 125HBL66

    3/8 Inch Barb X 3/8 Inch Pipe Brass Hose Fitting Replaces 10506B106, 125HBL66

    AUTOMANN USA

    $2.30
    3/8 Inch Barb X 3/8 Inch Pipe Hose Fitting* High Quality Hose Fitting* Hose Barb To Male NPT Connection* Use With 3/8" Push-On Hose* Made Of Brass* Barb Hose End: 3/8 Inch Inner Diameter* Male NPT...
    09-05040113
    SKU:
    09-05040113
    Material Options:
    Brass
    Product Type:
    Air, Electrical, & Safety
    Diameter Options:
    3/8 Inch
    Make:
    Universal Items
    $2.30
    Qty in Cart: 0
    Price:
    $2.30
    Subtotal:
  • 3/8 Inch Barb X 1/4 Inch Pipe Brass Hose Fitting Replaces 10506B104, 125HBL64

    3/8 Inch Barb X 1/4 Inch Pipe Brass Hose Fitting Replaces 10506B104, 125HBL64

    AUTOMANN USA

    $2.25
    3/8 Inch Barb X 1/4 Inch Pipe Hose Fitting* High Quality Hose Fitting* Hose Barb To Male NPT Connection* Use With 3/8" Push-On Hose* Made Of Brass* Barb Hose End: 3/8 Inch Inner Diameter* Male NPT...
    09-05040112
    SKU:
    09-05040112
    Material Options:
    Brass
    Product Type:
    Air, Electrical, & Safety
    Make:
    Universal Items
    $2.25
    Qty in Cart: 0
    Price:
    $2.25
    Subtotal:
  • 3/8 Inch Barb X 1/8 Inch Pipe Brass Hose Fitting Replaces 10506B102, 125HBL62

    3/8 Inch Barb X 1/8 Inch Pipe Brass Hose Fitting Replaces 10506B102, 125HBL62

    AUTOMANN USA

    $1.57
    3/8 Inch Barb X 1/8 Inch Pipe Hose Fitting* High Quality Hose Fitting* Hose Barb To Male NPT Connection* Use With 3/8" Push-On Hose* Made Of Brass* Barb Hose End: 3/8 Inch Inner Diameter* Male NPT...
    09-05040111
    SKU:
    09-05040111
    Product Type:
    Air, Electrical, & Safety
    Material Options:
    Brass
    Make:
    Universal Items
    $1.57
    Qty in Cart: 0
    Price:
    $1.57
    Subtotal:
  • 3/8 Inch Barb X 1/2 Inch Pipe Brass Hose Fitting Replaces 10506B108, 125HBL68

    3/8 Inch Barb X 1/2 Inch Pipe Brass Hose Fitting Replaces 10506B108, 125HBL68

    AUTOMANN USA

    $3.90
    3/8 Inch Barb X 1/2 Inch Pipe Hose Fitting* High Quality Hose Fitting* Hose Barb To Male NPT Connection* Use With 3/8" Push-On Hose* Made Of Brass* Barb Hose End: 3/8 Inch Inner Diameter* Male NPT...
    09-05040114
    SKU:
    09-05040114
    Material Options:
    Brass
    Product Type:
    Air, Electrical, & Safety
    Make:
    Universal Items
    $3.90
    Qty in Cart: 0
    Price:
    $3.90
    Subtotal:
  • 5/16 Inch Barb X 1/8 Inch Pipe Brass Hose Fitting Replaces 10505B102, 125HBL52

    5/16 Inch Barb X 1/8 Inch Pipe Brass Hose Fitting Replaces 10505B102, 125HBL52

    AUTOMANN USA

    $2.25
    5/16 Inch Barb X 1/8 Inch Pipe Hose Fitting* High Quality Hose Fitting* Hose Barb To Male NPT Connection* Use With 5/16" Push-On Hose* Made Of Brass* Barb Hose End: 5/16 Inch Inner Diameter* Male NPT...
    09-05040109
    SKU:
    09-05040109
    Product Type:
    Air, Electrical, & Safety
    Material Options:
    Brass
    Make:
    Universal Items
    $2.25
    Qty in Cart: 0
    Price:
    $2.25
    Subtotal:
  • 1/4 Inch Barb X 1/4 Inch Pipe Brass Hose Fitting Replaces 10504B104, 125HBL44

    1/4 Inch Barb X 1/4 Inch Pipe Brass Hose Fitting Replaces 10504B104, 125HBL44

    AUTOMANN USA

    $1.57
    1/4 Inch Barb X 1/4 Inch Pipe Hose Fitting* High Quality Hose Fitting* Hose Barb To Male NPT Connection* Use With 1/4" Push-On Hose* Made Of Brass* Barb Hose End: 1/4 Inch Inner Diameter* Male NPT...
    09-05040108
    SKU:
    09-05040108
    Material Options:
    Brass
    Product Type:
    Air, Electrical, & Safety
    Make:
    Universal Items
    $1.57
    Qty in Cart: 0
    Price:
    $1.57
    Subtotal:
  • 5/16 Inch Barb X 1/4 Inch Pipe Brass Hose Fitting Replaces 10505B104, 125HBL54

    5/16 Inch Barb X 1/4 Inch Pipe Brass Hose Fitting Replaces 10505B104, 125HBL54

    AUTOMANN USA

    $1.79
    5/16 Inch Barb X 1/4 Inch Pipe Hose Fitting* High Quality Hose Fitting* Hose Barb To Male NPT Connection* Use With 5/16" Push-On Hose* Made Of Brass* Barb Hose End: 5/16 Inch Inner Diameter* Male NPT...
    09-05040110
    SKU:
    09-05040110
    Material Options:
    Brass
    Product Type:
    Air, Electrical, & Safety
    Make:
    Universal Items
    $1.79
    Qty in Cart: 0
    Price:
    $1.79
    Subtotal:
  • 1/4 Inch Barb X 1/8 Inch Pipe Brass Hose Fitting Replaces 10504B102, 125HBL42

    1/4 Inch Barb X 1/8 Inch Pipe Brass Hose Fitting Replaces 10504B102, 125HBL42

    AUTOMANN USA

    $1.14
    1/4 Inch Barb X 1/8 Inch Pipe Hose Fitting* High Quality Hose Fitting* Hose Barb To Male NPT Connection* Use With 1/4" Push-On Hose* Made Of Brass* Barb Hose End: 1/4 Inch Inner Diameter* Male NPT...
    09-05040107
    SKU:
    09-05040107
    Product Type:
    Air, Electrical, & Safety
    Material Options:
    Brass
    Make:
    Universal Items
    $1.14
    Qty in Cart: 0
    Price:
    $1.14
    Subtotal:
  • 1/2 Inch Barb X 3/8 Inch Pipe Brass Hose Fitting Replaces 10508B106, 125HBL86, 1256

    1/2 Inch Barb X 3/8 Inch Pipe Brass Hose Fitting Replaces 10508B106, 125HBL86, 1256

    AUTOMANN USA

    $2.19
    1/2 Inch Barb X 3/8 Inch Pipe Hose Fitting* High Quality Hose Fitting* Hose Barb To Male NPT Connection* Use With 1/2" Push-On Hose* Made Of Brass* Barb Hose End: 1/2 Inch Inner Diameter* Male NPT...
    09-05040105
    SKU:
    09-05040105
    Product Type:
    Air, Electrical, & Safety
    Material Options:
    Brass
    Make:
    Universal Items
    $2.19
    Qty in Cart: 0
    Price:
    $2.19
    Subtotal:
  • 1/2 Inch Barb X 1/4 Inch Pipe Brass Hose Fitting Replaces 10508B104, 125HBL84

    1/2 Inch Barb X 1/4 Inch Pipe Brass Hose Fitting Replaces 10508B104, 125HBL84

    AUTOMANN USA

    $2.01
    1/2 Inch Barb X 1/4 Inch Pipe Hose Fitting* High Quality Hose Fitting* Hose Barb To Male NPT Connection* Use With 1/2" Push-On Hose* Made Of Brass* Barb Hose End: 1/2 Inch Inner Diameter* Male NPT...
    09-05040104
    SKU:
    09-05040104
    Product Type:
    Air, Electrical, & Safety
    Material Options:
    Brass
    Make:
    Universal Items
    $2.01
    Qty in Cart: 0
    Price:
    $2.01
    Subtotal:
  • 1/4 Inch Barb X 3/8 Inch Pipe Brass Hose Fitting Replaces 10504B106. 125HBL46

    1/4 Inch Barb X 3/8 Inch Pipe Brass Hose Fitting Replaces 10504B106. 125HBL46

    AUTOMANN USA

    $1.72
    1/4 Inch Barb X 3/8 Inch Pipe Hose Fitting* High Quality Hose Fitting* Hose Barb To Male NPT Connection* Use With 1/4" Push-On Hose* Made Of Brass* Barb Hose End: 1/4 Inch Inner Diameter* Male NPT...
    09-05040106
    SKU:
    09-05040106
    Product Type:
    Air, Electrical, & Safety
    Material Options:
    Brass
    Make:
    Universal Items
    $1.72
    Qty in Cart: 0
    Price:
    $1.72
    Subtotal:
  • Total: items /

Adding your products to cart

The Peterbilt 357 and 378 are known for their no-nonsense durability and old-school style. Whether you’re hauling heavy loads or running construction jobs, these workhorses are built to last—and we’re here to help you keep them in top shape.

Why Choose Aftermarket Peterbilt 357/378 Truck Parts?

- Engineered for your model: Every part is made to fit and function with your 357 or 378—so you can skip the guesswork and get back to work. - Performance you can count on: Keep your truck running strong with engine, transmission, suspension, fiberglass Pete 357/378 hood shells, LED headlights, and cab lighting accessories designed to turn heads. - Trusted brands, proven quality: We only carry parts from manufacturers we trust, so you know you're getting durable, road-tested gear. - Quick shipping, expert help: Get your parts fast and reach out to our team if you need help finding the right fit—we’ve got your back.

Shop the Perfect Aftermarket Accessories for Peterbilt 357/378 Trucks


Whether you're restoring a classic or keeping your work truck rolling, our Peterbilt 357 and 378 parts are built to match the strength and legacy of these iconic models. We stock a wide selection of aftermarket and replacement parts designed specifically for Peterbilt 357 and 378 models. From critical mechanical components to sleek interior cab accessory upgrades, we’ve got what you need to maintain, repair, or customize your rig. Explore our full selection and get the parts you need to keep your rig road-ready.

Frequently Asked Questions About Peterbilt 357/378 Parts

What years and models are compatible with Peterbilt 357/378 parts?

Most aftermarket parts for Peterbilt 357/378 trucks are designed to fit models from 1987 through 2007. However, there are important differences between early models (1987-1999) and later models (2000-2007), particularly in hood mounting points and grille configurations. Always verify the specific year range listed for each part, as some components like bumpers and fenders may have changed mounting hole patterns after the 2000 model year update.

Are aftermarket bumpers as durable as OEM Peterbilt bumpers?

Quality aftermarket bumpers are typically made from 16-gauge steel (same as OEM) and feature triple chrome plating or powder coating for corrosion resistance. The main differences you'll find are in the finishing details and fitment precision. While a well-made aftermarket bumper can last just as long as OEM, pay attention to the warranty offered - reputable manufacturers typically provide at least a 1-year warranty on chrome finish and 3-5 years on structural integrity.

What tools and modifications are needed to install replacement parts?

Most bolt-on parts like bumpers, grilles, and headlight assemblies require basic hand tools including socket sets (typically 1/2" to 3/4"), wrenches, and a drill with metal bits for any minor adjustments. Common installation challenges include slight drilling to align mounting holes (especially on pre-2000 models) and adjusting bumper brackets for proper fitment. Professional installation typically takes 2-4 hours for major components like bumpers or hoods.

What's the difference between chrome, stainless steel, and painted finishes?

Chrome-plated steel offers the brightest mirror finish but requires regular polishing and can pit in harsh climates. Stainless steel (usually 304 grade) provides excellent corrosion resistance with less maintenance but has a slightly duller appearance. Painted finishes are the most economical and can be color-matched to your truck, but may need repainting every 5-7 years depending on exposure. For winter driOEMg or coastal areas, stainless steel typically offers the best long-term value.

How do I ensure proper fitment when ordering hoods, fenders, or bumpers?

Start by confirming your exact model year and checking whether you have a standard or extended hood configuration. Measure key mounting points on your current parts before ordering - bumper width should be either 18" or 20" depending on your model. For hoods and fenders, verify whether you have the single-headlight or dual-headlight configuration. When in doubt, provide your OEM number when ordering to ensure compatibility, as some mid-year production changes aren't reflected in standard model year listings.


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