4WD Change for 2017?

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JExpedition07

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Fords limited slips aren’t known for lasting very long either.....
Thanks & yes Stock Vehicles. I'll have to study up on "differential" and "limited slip". I'm still learning.

I think that was his point sort of, but if one wheel stops turning at all ... which does seem to happen ... some potential traction being lost I think. Obviously I know squat though.

4x4 basically means all 4 wheels get power. Think of it this way a 4x2 vehicle in reality only has one wheel spinning, a 4x4 has two. All four wheels are getting equivent torque on a 4x4, but often only two will spin. Reason being is an open diff supplies both wheels on a given axle with the same amount of torque that of which the wheel with less traction can receive. So your wheel up in the air is getting x amount of torque and your wheel on the ground is also given that same amount of torque (not enough to roll forward) but it is getting power. So yes a 4x4 is sending equivent power to all 4 wheels, big BUT that is governed by the wheels with the least amount of traction. This is why we perceive only two as erring power but in reality all four are receiving torque. This is where braking bias or limited slip can assist further to send more power to the wheel with more traction. It gets confusing.

Now a locking differential locks the speed of the wheels on a given axle. Note to do this different torque must be applied to the different wheels as they have differing amounts of traction. So a locking diff supplies different torque to each wheel to lock the speed (hence we see both spin in tandem). The locking diff will send more torque to the wheel with traction while sending less to the wheel without (now it’s locked).

In this situation an open diff is sending the same amount of torque to both wheels. Say wheel x is in mud and wheel y is on pavement both wheels will receive the torque of wheel x with less traction. Now on a braking bias system wheel x will have the brakes clamped changing the perceived resistance forcing more power to wheel y (this is how they get around the issues of a conventional open diff).
 
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Black

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What do you consider not lasting long?

I have had 4 Fords with LSDs 2 went over 150k, 1 went 135k, the other went 85k.

All were still functioning flawlessly when I sold the vehicle or swapped the rear end conpletely.

Of course I swap to Amsoil gear oil and the proper friction modifier (when required) whenever I purchase a vehicle and never go over 50k without changing.
 
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JExpedition07

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Well the key is changing the fluid like you do, most don’t bother to do simple maintenance you have to remember. Many people have reported them going bad right out of the factory warranty.
 
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Black

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Well the key is changing the fluid like you do, most don’t bother to do simple maintenance you have to remember. Many people have reported them going bad right out of the factory warranty.

Cheap insurance. All differentials and transfer cases get Amsoil upon purchase and swapped no more than 50k. Transmissions get done at 50k as well.
Same with oil changes never go over 5k even when using full synthetic.
I haven’t done the Ex yet because I bought it with 46k. I’ll do it at 50k just to keep my change intervals with easy mileage numbers to remember.
Never lost a motor differential or transfer case.
Had to rebuild the T5 in my 92 Mustang at 80k but no less than 8 people learned to drive a stick on it and I was 16 so you know how that thing got driven.
 

Plati

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My 2014 EL Owners Manual says no fluid change until 150K

2014 SM.jpg
 

Black

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As does mine.
But fluids are cheap insurance.
Same with spark plugs they are cheap and easy they get done at 50k as well.
 

coolzzy

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I just bought a 17 XLT EL 4x4, and the VIN decoder says I have 3.73 with limited slip. I've looked at many and they don't all show that option so I'm not sure if it was just luck of the draw or what. I have the HD tow package and find it interesting that the transmission cooler is 7 rows vs the 4 row cooler on my max tow F150 that uses the same transmission.
 
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