Regearing F150
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Regearing F150
I have a '96 F150, 2WD, 4.9, 5-sp OD Mazda tranny, 3.55 gears. I'm thinking that I would like to change to 2.73 gears for better mileage (I have another truck for towing and heavy loads). I've been trying to learn more about what is required to make this change. Evidently any 8.8" rear end from '87-96 could be used, or I could change the ring and pinion in this rear end. I'm wondering about the speedometer calibration. Does it come from the sensor at the top of the differential? If so, does it stay calibrated even if you change ring and pinion? Otherwise, what do I need to do to recalibrate the speedometer? Thanks for any advice you can offer.
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Plan on spending 250-300 just on parts if you have the tools for a ring and pinion change. Add a couple hundred more if you have someone do it for you. As for as the speedo there is a procedure for recalbrating on this fourm i think.
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Joined: Oct 2006
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From: Redmond, WA
Originally Posted by shuttlevalve
Plan on spending 250-300 just on parts if you have the tools for a ring and pinion change. Add a couple hundred more if you have someone do it for you. As for as the speedo there is a procedure for recalbrating on this fourm i think.
If you plan on staying with the same size tires, you will not need to recalibrate. The PSOM uses the number of tire revolutions for 1 mile of travel to calculate. Changing the ring and pinion alone will have no effect on the number of revolutions your tire takes to reach one mile or your PSOM calibration.
By the way, you should be able to pick up a good R&P set for $200 or less.
Hope this helps
Mike
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From: Ottawa, Ontario
Your gearing change may not save you much fuel, you may find you need to downshift to climb hills, or drive in 4th at speeds below 50mph. Fuel consumption in an EFI engine is a function of engine load, so even though the gearing change will reduce rpm at any given speed, the engine will be under more load so the computer will add more fuel. What milage does the vehicle get now?
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Joined: Jun 2006
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From: Ottawa, Ontario
Yeah.. that's a bit low for the 4.9, but not ugly. You may see an improvement with a tuneup and replacement of the O2 and temp sensors if they have more miles on them. Has the check engine light ever been on? The 4.9 is torquey so it will pull more gearing than the small V8s can...
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