Im trying to get an FX4 model 04 150, however Ive never had a 4 wheel drive vehicle and have soem questions. 1st whats the diff between 4lo and 4hi 2nd why are you not supposed to drive at high sppeds or on road with 4x4 engaged and 3rd what sort of extra maintance do they require? Thanks Lots

 

Read the manual first off. BUt its "ok" to drive ont the road in 4HI. Its not great but its ok.. Dont do 4lo on the street.

 

There is a major difference between the low and high 4x4 setting. Each of those, utilze a different set of reduction gears in your transfer case. The 'high' setting is what you will use ~99% of the time. I have only used 4 'low' three or four times in the past 8 years (half of which were to pull a clydesdale out of the mud). Low can also be useful for pulling a boat out of the water, or similar activities, where low/no wheel spin and a ton of power are needed).

Are you looking at shift on the fly, or the standard manual shift 4x4? With the SOF system, you can shift in and out of 4 high at pretty much any reasonable speed (I think my 01 was 35mph...but your owners manual will tell you exactly what the speed is). For 4 low, that is not the case. You have to be at a complete stop, and have the transmission in neutral. Only then can you switch from 4 hi to 4 low.

You can use 4x4 on the street without any real worries, provided there is snow or otherise on the road! DO NOT, I repeat, do not drive on exposed tar with the 4x4 engaged. The way that all 4x4s leave the factory, are with two different axle ratios. Lets say your truck has 3.73 gearing. The front differential will actually have 3.72 gears. The reason this is done, is that your front wheels will spin slightly faster, which pulls the vehicle through a turn while engaged (otherwise the truck could likely 'push' in a snowy corner). The snow provides the lack of traction that is needed to keep the drivetrain from binding. If you think about it, the front end will effectively be pulling the truck faster than the rear tires can propel it. This can cause some serious driveline failures if you arent paying attention. Im not saying that if you see a dry spot of tar, on a snowy road, that you have to disengage. The key is understand the road conditions, and act appropriately.

Well there will be extra maintenance compared to a 2wd vehicle, but not that much more. Ball joints, tie rods, etc.. will all the the same from a 2wd, but U-joints and other 4x4 features are what you will need to watch. This new style Ford front end is actually a pretty reliable front end, with minimal effort needed to keep it in check. The same cannot be said about the old TTB F150 front suspension. Any other questions, let us know.


Rich

 

Thanks for the the reply wheelMA1 that really explained it well. Hopefully snow wont be a problem for awhile here in Florida but boat ramps 4x4 will come in handy plus the rainy season. Thanks again.

 

I'm not disagreeing with WheelMA, but I haven't heard them changing gear ratios between the front and rear since the old little bronco's, pre 76. Anyway snow isn't big problem here in S Jersey, but the most important thing to remember is not to make any sharp turns on dry pavement while in 4 wheel drive, high or low range. The transfer case in a true 4 x 4 locks the front axle to the rear axle. When you turn the rear wheels cut accross the inside of the circle and are turning less distance. This will cause the vehicle to hop as the tires break loose to realign themselves with the other axle. On sand, ice or snow you won't feel this while turning, but you will on dry pavement. If you do it enough to can turn the gears in the transfer case into dust, especially with big tires.


As long as you drive in a straight line it shouldn't hurt anything. When pulling a boat out of the water it's fine to use 4 wheel, but don't make a sharp turn at the top of the ramp without taking it out of 4 wheel or you'll feel the hop a mentioned above or worse yet gears breaking.


Other vehicles that use AWD(All Wheel Drive) are not true 4 wheel drives. Thier transfer cases have clutches in them to let front axle slip from the rear axle in turns. Most times they will supply most of the power to the rear wheels until they start to spin then the transfer case will delagate more power to the front axle. This type of 4 wheel drive is not nearly as effective as a 4 x 4 that locks the axles together.

I still don't trust this shift on the fly crap. I would much rather have the manual hubs out of the front axles. At least with that system you could still use low range without the front axle being in the act. I used my 88 Bronco that way to pull my buddy's 11,000lb 29ft Whaler out of the water all the time. With 7-800lbs of tongue weight on the hitch rear wheel traction isn't a problem.

 

shift on the fly is a good and proven system, as is the manual . just remember not to use it too much when the roads are dry...and even when it is raining. snow, sand and mud are when you'll be glad to have 4wd.....be sure to engage the SOF once a month or the manual shift ......