Picked up an '86 Fleetwood Jamboree with the Ford 460 carbureted engine. Two main issues:
The fridge isn't working at all. What should I check first for troubleshooting?
Also considering an EFI conversion on the 460 for better fuel economy since gas mileage is brutal. Is this upgrade cost-effective or should I stick with maintaining the carburetor system?
For the Jamboree fridge, check LP gas flow, burner for debris, and 12V power. Ford 460 EFI conversion costs more than the RV is worth - maintain the carburetor instead.
For your '86 Fleetwood Jamboree with the Ford 460, adding overdrive will significantly improve your fuel economy - expect to go from 6-7 mpg to 8-10 mpg. A transmission swap to an E4OD or 4R100 overdrive unit is your best bet and will cost $3,000-5,000 installed, but it will pay for itself in fuel savings over time. Regearing the rear differential is less effective and more expensive for the minimal gains you'll see. Focus on the overdrive transmission first, then tackle that fridge issue once you've got your drivetrain sorted.
Your '86 Jamboree came with a C6 3-speed automatic transmission that has no overdrive gear, which is why you're burning through gas at highway speeds. That 460 big block is spinning at high RPMs on the freeway, which is exactly what happened on your Vegas to SoCal trip. The engine is working much harder than it needs to for highway cruising.
The good news is that Ford's E4OD overdrive transmission can be adapted to work with your 460, though it requires modifications including crossmember changes and electronic control installation. This transmission was used in Ford trucks from 1989-1998 and provides a 0.75:1 overdrive ratio. When cruising at 65 mph, your engine RPM will drop significantly (actual figures depend on your differential ratio and tire size), which dramatically improves fuel economy.
Regearing your rear differential sounds appealing, but with your current 3.73 or 4.10 gears, going to taller gears like 3.31 will hurt your acceleration and hill climbing ability significantly. Your RV weighs 8,000-9,000+ pounds loaded, and you need that torque multiplication for mountain passes and merging onto highways.
For the transmission swap, you'll need a Ford E4OD transmission (1989-1997). Expect to pay $1,500-2,500 for a good rebuilt unit. You'll also need the matching torque converter, transmission cooler lines, and the electronic control module that operates the overdrive and lockup functions.
The total project cost typically runs $3,000-5,000 depending on whether you go with a basic rebuilt unit or a performance-built transmission. Many RV owners find that transmission shops specializing in motorhomes offer package deals that include everything needed for the swap.
This is definitely not a weekend DIY project unless you have serious transmission experience and a well-equipped shop. The E4OD swap requires removing the existing C6, modifying the transmission crossmember, running new wiring for the electronic controls, and programming the transmission control module to work with your carbureted 460 engine. This electronic transmission integration with the carbureted engine requires additional modifications and expertise.
The installation typically takes 2-3 days at a shop. They'll need to drop the transmission, modify mounting points, run the new wiring harness into the cab, and calibrate the electronic controls. Most shops that do this swap regularly can have you back on the road quickly.
After the installation, plan on a break-in period where you avoid heavy towing or high speeds for the first 500 miles. The transmission will need a fluid and filter change at 1,000 miles, then regular maintenance every 30,000 miles thereafter.
This project absolutely requires professional installation unless you're an experienced transmission technician. The electronic controls and calibration are complex, and mistakes can be expensive. Look for transmission shops that advertise motorhome services - they'll have done this swap many times on similar coaches.
Get quotes from at least three shops, and ask to see photos of previous Jamboree conversions they've completed. A good shop will warranty the work for at least 12 months or 12,000 miles. Expect the project to take 3-5 days from drop-off to pickup.
Before committing to the transmission swap, also get your fridge diagnosed. For your 1986 Jamboree's absorption refrigerator, common issues include: dirty burner assembly (clean annually), faulty control board ($150-300), bad thermistor ($50-100), or cooling unit failure ($800-1200). Start by checking if the unit lights on propane - if not, check the control board and thermistor first. If it lights but doesn't cool, the cooling unit may need replacement. Always ensure proper ventilation and level parking for optimal operation.
The transmission upgrade is a significant investment, but many Jamboree owners report that the improved drivability and fuel savings make it worthwhile for anyone planning to use their coach regularly. With current gas prices, the payback period will vary based on your driving habits, fuel costs, and actual mileage improvement achieved.
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