Ford 3.7L Engine Swap

Swapping a Ford 3.7L Engine into a 1983-2011 Ford Ranger

Short answer: It’s doable — many owners have dropped a Ford 3.7L (Cyclone/Duratec 3.7) into older Rangers — but it’s a medium-to-major custom swap. The big hurdles are mechanical fit (mounts, oil pan, firewall/clearance), driveline/transmission compatibility, and the electronics (engine harness + PCM/immobilizer). If you plan carefully and bring the right donor pieces (or buy a swap harness/standalone ECU), you can make it work.

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1) Which 3.7L Are We Talking About?

Ford’s 3.7L “Cyclone” / Duratec 3.7 V6 (introduced around 2007) is used in the F-150, Mustang, and several other Ford models. It’s a modern aluminum V6 with variable cam timing and chain-driven accessories — strong, efficient, and reliable, but not a simple bolt-in for an older Ranger.

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2) Engine Specs

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3) Major Obstacles

1. Engine mounts & clearance: The 3.7’s mount points, oil pan shape, and valve-cover position can interfere with the Ranger firewall, crossmember, and steering. Expect to use custom mounts or adapter plates and possibly clearance work on the firewall.
2. Transmission & driveline: Decide whether to use the Ranger transmission (with adapters) or the donor’s transmission. Bellhousing pattern, starter position, pilot bearing, and input shaft spline count must all match. You may need driveshaft and crossmember modifications.
3. Electronics (harness & PCM): Modern 3.7L engines require their PCM and full engine harness. You’ll either need to transplant the donor’s immobilizer modules and keys, or run a standalone ECU. Integrating the harness into the Ranger chassis (power, starter, fuel pump, cluster) is one of the hardest parts.
4. Exhaust & intake: The manifolds and exhaust routing will likely require custom fabrication. Intake routing and MAF placement must match the donor PCM calibration.
5. Cooling & accessories: The radiator, hoses, and accessory drives (A/C, P/S, alternator) may not align with the Ranger mounts. You may need to use the donor’s cooling system or custom brackets.
6. Legal & emissions: Swapping in a newer engine may trigger emissions or inspection requirements depending on your state. Always confirm legality before starting the project.

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4) Donor Components You’ll Need

Essential (strongly recommended):

• Complete 3.7L engine assembly (long block with oil pan and intake)
• Complete engine wiring harness
• PCM/ECU and immobilizer modules (plus donor keys)
• All sensors (cam/crank, MAP/MAF, TPS, O2, temp, etc.)
• Throttle body and pedal assembly (if drive-by-wire)
• Alternator, starter, and accessory brackets
• Exhaust manifolds/downpipe
• A/C compressor, power steering pump, and brackets
• Flywheel/flexplate and clutch or torque converter for your transmission choice
• Engine mounts (donor or custom fabricated)
• Radiator and electric fans (if compatible)
• Fuel rail, injectors, and regulator

Optional but helpful:

• Donor transmission
• Donor ABS/BCM modules (helps with immobilizer issues)
• Sub-harnesses for starter, alternator, and cluster connections

Tip: Always get the engine harness, PCM, and keys together from the same donor vehicle — it saves major headaches later.

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5) Step-by-Step Plan

1. Define your goals: Daily driver, off-road toy, or performance build? Decide early whether to keep the Ranger transmission or use the donor’s.
2. Choose your donor: Pick a donor year that uses a similar PCM generation. Ideally, get the full engine bay harness and PCM together.
3. Harvest components: Take the engine, harness, PCM, keys, intake, manifolds, alternator, starter, radiator, and accessories. Label every connector.
4. Mock fit the engine: Test-fit in the Ranger bay. Check for firewall, steering, and hood clearance. Modify only where needed.
5. Mounts & crossmember: Fabricate or adapt mounts for proper engine position and driveshaft alignment.
6. Transmission mating: Bolt the engine to the transmission (or use the donor trans). Confirm starter position and driveshaft length.
7. Wiring & PCM integration:
   • Full transplant: use donor PCM and modules.
   • Patch harness: splice engine harness into Ranger chassis.
   • Standalone ECU: eliminates immobilizer but adds cost.
8. Fuel system: Upgrade pump and lines to match 3.7L fuel pressure requirements.
9. Cooling & exhaust: Fit radiator, fans, and fabricate the exhaust.
10. Sensors & emissions: Ensure all O2 sensors and check-engine light circuits function.
11. Tuning & programming: Flash or tune the PCM for the correct vehicle and transmission setup.
12. Final checks: Verify leaks, charging system, cooling, and drivability before first test run.

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6) Time, Cost, and Difficulty

• Time: 1–4 weeks for a shop; several months for a DIY build.
• Cost: $1,500–$6,000 (DIY donor build) or $8,000–$15,000 (professionally wired and tuned).
• Difficulty: Moderate to high. The hardest parts are wiring/PCM integration and transmission fitment.

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7) Tips to Simplify the Swap

• Use the donor transmission — it avoids adapter headaches.
• Get a complete donor engine bay if possible.
• Buy an aftermarket patch harness or standalone ECU.
• Study swap threads and wiring diagrams before cutting anything.

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8) Quick Checklist

• ✔ Choose donor year and PCM generation
• ✔ Acquire engine, harness, PCM, and keys
• ✔ Get flywheel/flexplate, clutch, or torque converter
• ✔ Plan engine mounts and crossmember modifications
• ✔ Decide transmission setup
• ✔ Prepare cooling, exhaust, and fuel systems
• ✔ Integrate or replace wiring/ECU
• ✔ Tune PCM and test-drive
• ✔ Check emissions legality

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9) Final Recommendations

If you want fewer surprises, use a complete donor drivetrain (engine + transmission + harness + PCM). Budget extra time for wiring and tuning — that’s where most swaps succeed or fail. Join Ranger and Mustang/F-150 swap communities to reference pinouts, adapter notes, and real-world tips before starting the project.

With the right donor and planning, a 3.7L swap can transform a Ranger into a powerful, modern daily driver or off-road rig.

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3.7L & 6R80 Swap Parts List for the 1983-2011 Ford Ranger

Using the 6R80 transmission from the donor vehicle is the smartest approach for this swap. It eliminates the complexity of adapting the 3.7L Cyclone engine to the Ranger’s older transmissions. Below is a detailed list of what you’ll need to successfully integrate the 3.7L and 6R80 drivetrain into a 1998–2011 Ford Ranger.

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1) Core Drivetrain Components (From Donor Vehicle)

You want the entire engine-transmission package as a matched pair — Ford’s control system expects them together.

• 3.7L Cyclone V6 engine (complete long block with accessories)
• 6R80 6-speed automatic transmission
• Torque converter
• Flexplate and bolts
• Flexplate spacer (if equipped)
• Bellhousing bolts
• Starter motor (specific to the 3.7/6R80 combo)
• Engine mounts (for modification or mockup)

Tip: The 2011–2014 Mustang or F-150 drivetrain is the easiest to work with. Later years (2015+) use different PCM logic and CAN bus systems.

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2) Electronics & Wiring

This is the most complex part of the swap. Gather every related component from the donor to simplify integration.

• PCM (Powertrain Control Module) – matched to the 3.7L/6R80 calibration
• Full engine wiring harness
• Transmission harness
• Body-to-engine harness pigtail (if possible)
• PCM connectors with a few inches of wire for splicing
• Drive-by-wire (DBW) pedal assembly
• MAF sensor and airbox
• Throttle body (matches PCM calibration)
• O2 sensors (upstream and downstream)
• Cam and crank sensors (included on engine)
• Neutral Safety Switch (TRS) on the 6R80
• Range selector / shift lever switch (if separate)

Optional but helpful:

• Donor BCM (Body Control Module), Smart Junction Box, PATS transceiver, and key(s)
• Aftermarket standalone control pack (Ford Performance or Power By The Hour)

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3) Transmission-Related Parts

• 6R80 transmission crossmember – modify the Ranger unit or fabricate a custom mount
• Transmission mount (urethane or rubber)
• Custom driveshaft – match 6R80 output spline and Ranger rear flange; adjust length
• Shift cable or electronic shifter – Mustang/F-150 cable can be adapted
• Transmission cooler and AN lines (use donor or aftermarket stacked-plate cooler)
• Cooler fittings/adapters for 6R80 (1/2″ quick connect or AN-6)

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4) Fuel, Cooling, and Exhaust Systems

Fuel system:

• Returnless high-pressure system (~58 psi)
• Upgraded in-tank fuel pump (Walbro 255 or equivalent)
• 3/8″ feed line and 5/16″ return line (if using donor rail setup)
• Donor fuel rail and injectors

Cooling system:

• Donor radiator and dual electric fans (or custom aluminum radiator)
• Coolant hoses (mix of donor and custom)
• Expansion tank (closed cooling system)

Exhaust system:

• Donor exhaust manifolds (usually best fit)
• Custom downpipes and Y-pipe
• O2 sensor bungs (for upstream and downstream sensors)
• Catalytic converters (for emissions compliance)

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5) Electronics Integration & Control Options

There are three ways to manage engine and transmission control:

Option 1: Donor PCM + BCM + Keys (Full Transplant)

• Factory calibration and CAN logic remain intact
• Retains PATS (anti-theft) system
• Requires integration of donor fuse box and CAN bus wiring
• Best option if you have the entire donor engine bay harness

Option 2: Ford Performance Control Pack

• Standalone plug-and-play harness
• Includes PCM, pedal, fuse box, OBD-II port, and base tune
• Controls both engine and 6R80 transmission
• More expensive (~$1,500–$2,000)

Option 3: Custom Standalone Harness

• Available from Power By The Hour (PBH), Ron Francis, or built DIY
• Integrates easily with the Ranger’s chassis harness
• Recommended if you cannot get full donor electronics

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6) Mounting & Fabrication

• Custom engine mount brackets (bolt-in or welded)
• Custom or modified transmission crossmember
• Custom driveshaft and yoke
• Exhaust routing modifications
• Shifter mount (floor or column style)
• Minor firewall or oil pan clearance adjustments if needed

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7) Optional & Recommended Parts

• Upgraded alternator wiring (3G/4G-style upgrade)
• Electric fan relay kit
• Transmission dipstick kit (Lokar-style)
• Transmission temperature gauge
• PCM tuning cable (HP Tuners, SCT, or similar)
• ECU mounting bracket

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8) Summary: Required Components Overview

Category	Required Parts
Engine	3.7L Cyclone V6 (complete long block, accessories, sensors)
Transmission	6R80 automatic, torque converter, flexplate, crossmember
Electronics	PCM, harnesses, DBW pedal, MAF, O2 sensors, PATS/key or control pack
Cooling	Radiator, hoses, electric fans, transmission cooler
Fuel	High-pressure pump, lines, donor injectors/rail
Driveline	Custom driveshaft, mount, shift linkage
Exhaust	Donor manifolds, Y-pipe, O2 sensors, catalytic converters
Controls	Shifter, transmission cooler, standalone harness or PCM integration
Tuning	ECU programming (base tune or custom dyno tune)

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9) Pro Tips

• Use a 2011–2014 Mustang or F-150 donor for the cleanest wiring and tuning setup.
• The F-150 6R80 uses a truck-style tailhousing that aligns better with Ranger driveshaft geometry.
• When pulling the donor, label every connector and take 6–8 inches of wire lead from each plug.
• Keep the PCM, BCM, and keys together if not running a standalone control pack.
• Consider a Power By The Hour (PBH) or US Shift Quick 6 standalone transmission controller.
• Budget around $4,000–$6,000 for a donor drivetrain and harness, plus $1,500–$3,000 for fabrication and tuning.

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10) Summary

Using the 6R80 transmission with the 3.7L engine makes for a far more reliable and capable swap. The drivetrain is strong, efficient, and offers smooth shift logic once properly tuned. The key is sourcing as many components as possible from a single donor vehicle and taking the time to integrate the wiring correctly.

With the right donor and planning, the 3.7L + 6R80 combination can transform your Ranger into a modern, powerful daily driver or off-road rig.