FIRCHASSIS FIRC3877860SS Front Rear Tank Diesel Sending Unit

( Brand: Firchassis ), ( Manufacturer Part Number: FIRC3877860SS ), ( Type: Fuel Sending Unit ), ( Fuel Type: Diesel ), ( Items Included: Mounting Hardware ), ( Placement On Vehicle: Fuel Tank ), ( Oe/oem Part Number: Fmsu-6der Fmsu-6de ), ( Voltage: 12 V ), ( Manufacturer Warranty: 1 Year )

Review FIRCHASSIS Ford Front And Rear Side Tank Diesel Pickup Sending Unit fits F250 F350 1985–1986

The **FirChassis FIRC3877860SS** is a high-performance, direct-fit diesel fuel sending unit designed specifically for Ford F-Series trucks, including the iconic **1985 1986 F-250 and F-350 models** equipped with **7.3L (225 cubic inch) diesel engines**. Engineered to meet the exacting demands of modern diesel applications while maintaining seamless compatibility with the original vehicle architecture, this sending unit is crafted from durable, corrosion-resistant materials to ensure long-term reliability in both on-road and off-road environments. Its sleek, streamlined design integrates a **high-precision float mechanism** and a **robust electrical connector**, delivering accurate fuel level readings to the vehicle s gauge or diagnostic system with minimal signal drift. Ideal for restorers, performance enthusiasts, and fleet operators seeking to upgrade or replace worn-out or malfunctioning OEM components, this unit eliminates common issues such as erratic fuel level indicators, gauge failure, or sensor inaccuracy, which can stem from degraded seals, rusted housings, or faulty wiring interfaces. The **SS (Stainless Steel) variant** further enhances durability, resisting the harsh conditions of salt-laden highways, off-road dust, and prolonged exposure to moisture making it a premium choice for trucks subjected to heavy-duty use. Whether installed in a classic restoration project or as part of a routine maintenance upgrade, the FirChassis FIRC3877860SS ensures consistent performance, compatibility with modern diesel fuel systems, and peace of mind for drivers who demand both precision and longevity from their vehicle s critical components.

### **Pros and Cons of Buying a FirChassis FIRC3877860SS Diesel Fuel Sending Unit for 1985-1986 Ford F-250/F-350**

1. **Compatibility** The FirChassis FIRC3877860SS is specifically designed for 1985-1986 Ford F-250/F-350 diesel models, ensuring a proper fit without modifications.

2. **Reliability** FirChassis is a reputable manufacturer known for producing high-quality aftermarket parts, reducing the risk of premature failure.

3. **Fuel Level Accuracy** A properly functioning sending unit ensures accurate fuel gauge readings, preventing false low-fuel warnings or erratic behavior.

4. **Durability** The unit is built to withstand the demands of diesel fuel systems, reducing the likelihood of corrosion or mechanical wear over time.

5. **Ease of Installation** Since it is a direct replacement, installation is straightforward, requiring minimal tools and expertise.

6. **Cost-Effective** Compared to OEM replacements, this aftermarket unit is often more affordable while maintaining performance and reliability.

7. **Warranty Coverage** FirChassis typically offers warranties, providing some assurance against defects in materials or workmanship.

1. **Potential Quality Variations** While FirChassis is generally reliable, there is always a slight risk of receiving a defective unit, especially if purchasing from an unverified seller.

2. **Compatibility with Modified Systems** If the vehicle has undergone fuel system modifications (e.g., upgraded injectors, turbochargers, or fuel pumps), the sending unit may not integrate perfectly with new components.

3. **Limited Availability** Depending on the region, finding this specific part may require ordering from an online retailer, which could introduce shipping delays.

4. **Price Sensitivity** While often cheaper than OEM parts, some buyers may find the cost slightly higher than generic aftermarket alternatives, though this depends on the source.

5. **Installation Challenges** If the vehicle has been heavily modified or has rusted fuel lines, installation could be more difficult than expected, requiring extra effort or professional help.

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The FirChassis FIRC3877860SS diesel fuel sending unit is a strong choice for 1985-1986 Ford F-250/F-350 owners needing a reliable replacement. Its compatibility, durability, and accuracy make it a practical solution for restoring proper fuel gauge function. However, buyers should ensure they purchase from a trusted supplier to avoid counterfeit or damaged units. If the vehicle has significant modifications, additional testing may be necessary to confirm seamless integration.

If you are experiencing fuel gauge issues in your 1985-1986 Ford diesel truck and need a direct replacement, the FirChassis FIRC3877860SS is a solid option. To maximize satisfaction:

- **Purchase from an authorized dealer or reputable online retailer** (e.g., FirChassis s official website, RockAuto, or specialized diesel parts suppliers).

- **Verify compatibility** with any aftermarket fuel system upgrades.

- **Follow installation guidelines carefully** to avoid damage to the fuel system.

- **Consider testing the gauge** after installation to ensure accurate readings.

For most users, this part will provide a dependable fix without major drawbacks, making it a recommended choice for this application.

Details:

Stable characteristic, high reliability. It is a good choice to replace an old one. New List Item. Unique charm, wear-resisting durable and undamaged.

Easy to install. All original hardware must be included in the package. For Ford F250 F350 1985 1986 Front Rear Side Tank Diesel Pickup Sending Unit. Front,Midships,Side Tank.

Item Specifics: Brand FirChassis, Type Fuel Sending Unit, Diesel, Items Included Mounting Hardware, Placement on Vehicle Tank, Manufacturer Part Number FIRC3877860SS, OE/OEM FMSU-6DER FMSU-6DE, voltage 12 V, Warranty 1 Year. No drilling and cutting required. 2 Diesel Pickup Sending unit. For Ford F250/350 1985 -1986.

part #: firc3877860ss prices

• $21.07-$43.18

specifications fueltanksysteme:

• for models: F250, F350
• for makes: Ford
• for years: 1985-1986
• brand: Firchassis
• mpn: Firc3877860ss
• type: Fuel Sending Unit
• fuel type: Diesel
• items included: Mounting Hardware
• placement on vehicle: Fuel Tank
• oe/oem part number: Fmsu-6der Fmsu-6de
• voltage: 12 V
• manufacturer warranty: 1 Year

returns fueltanksysteme:

• paid by: Seller
• time: 30 Days
• policy: Returns Accepted

shipping fueltanksysteme:

• class: Standard
• service: Standard
• type: Fixed
• transit: 3-8 Days
• cost: $0.00

payments fueltanksysteme:

• wallet: Apple-pay
• other
• credit card: Visa

offer fueltanksysteme:

• sold: 0
• options: Ship-to-home
• started: February 25, 2026
• quantity: 2
• availability: In Stock
• best offers: True

general fueltanksysteme:

• condition: New
• Car Truck Parts Accessories > Air Fuel Delivery > Fuel Pumps Sending Units

seller fueltanksysteme:

• rating: 98.8%
• city: Chino, California
• # reviews: 1105

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