Why not just leave it in 4A for daily?

[HugAFreak]

My Raptor is my daily and 90% of the time it's regular roads and some twisty stuff. Once it's warmed up I switch to sport mode. What, if any, are the downsides of just staying in 4A vs 2H? Worse MPG?

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[sikedsyko]

MPG and clutch wear. 4A uses an electronically controlled clutch to engage the front wheels. Anytime the 4A torque request to the front wheels isn't 0/50% its going to be slipping the clutch.

In practice its probably fine, most AWD crossovers these days use a similar mechanism and you don't have any way to turn it off.

 

[Aonarch]

MPG and clutch wear. 4A uses an electronically controlled clutch to engage the front wheels. Anytime the 4A torque request to the front wheels isn't 0/50% its going to be slipping the clutch.

In practice its probably fine, most AWD crossovers these days use a similar mechanism and you don't have any way to turn it off.

Agreed.

In practice it is fine, plenty of F-150 drivers leave it in 4A every day for 100k miles plus, and the F-150 has a similar TC design.

But as stated, you will see reduced MPG and increased TC clutch wear.

It is better to leave it in 2H for most driving situations.

But if there is rain, snow, ice, etc, you can leave it in 4A the entire time.

If you use 4A often, I'd change your transfer case (TC) fluid every 30k miles. It is crazy easy to do and very inexpensive.

 

[Jason B]

Why reduced MPG? Weather in 4WD or 2WD, the front axles and drive shaft are always turning.
And what about 'slipping the clutch'. Your AC compressor uses and electric clutch, would say leave it running all the time so as not to prematurely wear the clutch?

 

[Roguescholar]

While you won’t break anything on the Ranger Raptor by leaving it in 4A all the time, it’s usually better to stick to 2H for daily driving on dry roads. Keeping it in 4A means the front axle and hubs are constantly spinning, which creates extra mechanical drag, hurts fuel economy, and adds unnecessary wear to the front differential over time. You might also notice that the steering feels a bit heavier or slightly drags during tight turns.

The main time I used to use 4A was when road conditions could quickly change, like when there were varying amounts of ice on the road following a storm.

 

[HugAFreak]

I live in NH, so yeah 4A will make a lot of sense in Fall & Winter. I guess I'll stick to 2H for now unless I'm doing 0-60 drags at the lights!

 

[sikedsyko]

Why reduced MPG? Weather in 4WD or 2WD, the front axles and drive shaft are always turning.
And what about 'slipping the clutch'. Your AC compressor uses and electric clutch, would say leave it running all the time so as not to prematurely wear the clutch?

The front axles disconnect at the hubs when you're in 2WD.

AC Compressor clutch is going to be either on or off at all times except the fraction of a second while its engaging. The Ranger doesn't have a torque split display, but some other Fords do. My wife's Bronco Sport has one and you can see that the car is pretty frequently requesting a torque split that would require the clutch to slip. Like I say, its normal operation for lots of vehicles. I'm sure its not that hard or expensive to replace relative to a $60k truck and would probably be a ~100k mile type service if you're using 4A all the time.

Its the same reason you can't do extended offroading in clutch based AWD systems, because they overheat the clutch slipping it and have to completely disengage the clutch for a while to let the system cool down. If you have heavy needs for full time AWD a differential based system works better.

 

[Sparkherd]

The front axles disconnect at the hubs when you're in 2WD.

WHAT? Ranger 6 gen has disconnecting front hubs?!?
When did this happen?
Why nobody told me?!?

 

[Jason B]

The front axles disconnect at the hubs when you're in 2WD.

AC Compressor clutch is going to be either on or off at all times except the fraction of a second while its engaging. The Ranger doesn't have a torque split display, but some other Fords do. My wife's Bronco Sport has one and you can see that the car is pretty frequently requesting a torque split that would require the clutch to slip. Like I say, its normal operation for lots of vehicles. I'm sure its not that hard or expensive to replace relative to a $60k truck and would probably be a ~100k mile type service if you're using 4A all the time.

Its the same reason you can't do extended offroading in clutch based AWD systems, because they overheat the clutch slipping it and have to completely disengage the clutch for a while to let the system cool down. If you have heavy needs for full time AWD a differential based system works better.

Thanks. I can see that something has to give, since it's not just an on-off thing.
The disconnecting hubs must be a Raptor thing, because it's not on FX4 XLT. Then again, we don't get locking diff on our front axles.

 

[momike]

At the risk of hijacking this thread, I've been wondering about drive modes for off-road.

Both off road mode and Baja mode have the rear diff locked by default. But I read that locking diffs are stressed except in very loose terrain.

What mode is best to use for flying around on dirt, rocky, and variable roads (as opposed to sand etc).

 

[jordantii]

One advantage to 4A on dry pavement is better handling. It gets rid of most of the understeer on throttle application coming out of a corner. I figured this out about 2 weeks ago...

 

[CaptAngry]

The hubs do NOT disconnect on these trucks (or any modern truck that I can think of). Everything spins all the time. The only disconnecting of anything (outside of lockers) is inside the transfer case

On a modern Ranger Raptor, there are no mechanical axle or driveshaft disconnect locations anywhere in the front end.

1. No Hub Disconnects (Free-Wheeling Hubs)
   The front wheel hubs are permanently locked to the front half-shafts (CV axles). There are no automatic vacuum-operated or manual locking hubs at the wheels.
2. No Center Axle Disconnect (CAD)
   The truck does not use a front axle split-shaft disconnect mechanism (CAD). The front half-shafts are permanently splined directly into the front differential carrier.'

Because there are no disconnect points, the front wheels, front CV axles, front differential gears, and the front driveshaft spin continuously whenever the vehicle is moving, even when you are driving in 2H mode. The only "disconnect" that actually occurs happens inside the central transfer case. When you select 2H, the internal multi-plate clutch pack completely releases. This cuts off the engine's power flow to the front driveshaft. The front drivetrain continues to rotate, but it is being "back-driven" by the front wheels rolling along the pavement rather than being driven by the engine.

 

[scrappyisbe]

WHAT? Ranger 6 gen has disconnecting front hubs?!?
When did this happen?
Why nobody told me?!?

They DON'T!!

 

[sikedsyko]

I swear I read early in the release cycle on Ranger Raptor that it had disconnecting hubs.

 

[Jason B]

I swear I read early in the release cycle on Ranger Raptor that it had disconnecting hubs.

Maybe you got it confused with the Electronic-Locking Front Axle, which locks the differential, something only Raptor has. FX4 has locking rear axle, but not front axle.

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