2018 F-150 4x4 differentials
07-06-2018, 04:12 PM
#41
Agreed. All good. 
Just terminology and how we look at it. For the record, I don't even have 4A on my truck. I just like to learn about all this stuff. Haha.
KG7BTU's post above is accurate.
To answer your question in short, in 2A, the front hubs and drivetrain are completely disengaged. That's a big benefit of Ford over some of its competitors. Reportedly that results in fuel savings and less wear-and-tear on the front drivetrain. That's why it's better to run in 2Hi most of the time.
As for the IWE's, to summarize, it's a vacuum system. It's the opposite of what you might think... when the vacuum is OFF, the front wheels are *engaged*. When the truck is powered and the vacuum is activated, the hubs are disengaged. Presumably this is so that if there is a vacuum failure, the front hubs will be engaged for 4wd use and you won't be stuck in the woods. Keep in mind that in this instance, that 4wd isn't engaged until you put the truck in 4Hi and actually engage the front driveshaft. But the hubs themselves would be engaged.
BTW, I think you mentioned Sport mode (for the transmission) earlier. That can be used any time you like. I've seen it mostly holds the gears longer, for example it will stay in 5th gear much longer, before shifting to 6th. Under 60mph, it may stay in 5th most of the time giving better throttle response (though at the cost of fuel, so I only run it when necessary).
Just terminology and how we look at it. For the record, I don't even have 4A on my truck. I just like to learn about all this stuff. Haha. Very interesting. Hey, do you happen to have a link or something how that works? Thank you for letting us know what kind of transfer case we have; it's good to know. But I don't quite grasp how the IWE (integrated wheel something, which doesn't make a whole lot of sense what it does. Ha ha) works, and how. Specifically, with the mode in 2WD, everything is turning, right? So there shouldn't be any fuel savings over running 4A, no? But still, the manual says to run 2H on the streets and traveling on pavement, suggesting it's not a true AWD system that you just always leave it there, or it's always there, like Audi Quattros and Subarus. But definitely good enough for my needs. If it ever gets slippery due to rain, snow, etc., we can switch it on.
FInally, since you seen to know a lot about this, do we have to back up in reverse after using either the locking differential or 4A, 4H or 4L modes? Just curious. Thanks man.
FInally, since you seen to know a lot about this, do we have to back up in reverse after using either the locking differential or 4A, 4H or 4L modes? Just curious. Thanks man.
To answer your question in short, in 2A, the front hubs and drivetrain are completely disengaged. That's a big benefit of Ford over some of its competitors. Reportedly that results in fuel savings and less wear-and-tear on the front drivetrain. That's why it's better to run in 2Hi most of the time.
As for the IWE's, to summarize, it's a vacuum system. It's the opposite of what you might think... when the vacuum is OFF, the front wheels are *engaged*. When the truck is powered and the vacuum is activated, the hubs are disengaged. Presumably this is so that if there is a vacuum failure, the front hubs will be engaged for 4wd use and you won't be stuck in the woods. Keep in mind that in this instance, that 4wd isn't engaged until you put the truck in 4Hi and actually engage the front driveshaft. But the hubs themselves would be engaged.
BTW, I think you mentioned Sport mode (for the transmission) earlier. That can be used any time you like. I've seen it mostly holds the gears longer, for example it will stay in 5th gear much longer, before shifting to 6th. Under 60mph, it may stay in 5th most of the time giving better throttle response (though at the cost of fuel, so I only run it when necessary).
07-06-2018, 05:52 PM
#42
FORD lifer
It's a mechanical LSD, so no synthetic oil, just boring old 80W90 oil, and change it every 30k.
It's 30% stronger, to take Raptor torque, and the 'bias' is set so as to not make the steering any heavier than they have to.
07-06-2018, 07:29 PM
#43
So where the heck area those 'hubs'? Can't find any pictures. MUCH better to understand that way. From the TOD transfer case, the shaft goes to the front differential, correct? And from the diferential, the front shafts to the wheels. So where the heck they disengage??? Thx.
07-06-2018, 07:57 PM
#44
Senior Member
This is just the first video link from my search, looks like he points them out. They are built into the hub... not sure how to explain further than that.
Video:
Video:
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Florida_F150 (07-06-2018)
07-06-2018, 08:22 PM
#45
This is just the first video link from my search, looks like he points them out. They are built into the hub... not sure how to explain further than that.
Video: https://youtu.be/148Eal6lBX8
Video: https://youtu.be/148Eal6lBX8
07-06-2018, 09:12 PM
#46
Senior Member
You didn't read carefully enough @moparado. I never mentioned anything about traction control. What I did very specifically mention is that vehicle handling is far better in plain jane 4X4 drive than having a locked rear end.
4x4 drive on gravel with out the electronic rear end locked in, I don't spin at all. Honestly I haven't been very impressed with the electronic locking rear end in this ford,it really doesn't make much of a difference.
4x4 drive on gravel with out the electronic rear end locked in, I don't spin at all. Honestly I haven't been very impressed with the electronic locking rear end in this ford,it really doesn't make much of a difference.
I was referring and i think montanaman also to a 1/4 mi. drag race on gravel with a rear LSD vs. rear traction control in rear wheel drive only.
In that 1st post, you were touting the dis-advantage of an LSD on gravel which is BS.
Sure both LSD tires will spin initially but vs. an open rear diff with only traction control, good luck.
Now you're claiming that gravel drag race should be done in 4X4 and with an elocker?
Last edited by moparado; 07-06-2018 at 09:28 PM.
07-06-2018, 10:04 PM
#47
Specifically, with the mode in 2WD, everything is turning, right? So there shouldn't be any fuel savings over running 4A, no? But still, the manual says to run 2H on the streets and traveling on pavement, suggesting it's not a true AWD system that you just always leave it there, or it's always there, like Audi Quattros and Subarus.
I just wanted to clarify one misconception in the above: The manual clearly says that 4A is suitable for all road conditions. It does not caution against using 4A on dry pavement, etc., as it does regarding 4H.
I know some people here caution against it anyway, but fwiw I run my Lariat in 4A pretty much all the time (unless I need 4H or L, which is rare). It’s never given me any trouble in many thousands of miles.
07-07-2018, 03:03 AM
#48
Just read the entire section of the manual again (not the best written). Was reading the '2-speed automatic 4WD (don't know what the hell that is), but after that, it's the '4A' section, and it clearly states 4A is suitable for all 'on-road driving conditions', but only in normal and sport modes. So you were correct. Thank you for pointing that out. And with your testimonial, it's obviously okay to use it all the time. That is very good news to those who develop issues with the IWEs. Rather than risk damage, I'd just engage 4A until it's fixed, probably with a new check valve.
And thanks a lot for tha IWE video. It clearly shows where the IWEs are. Never heard of that system. Interesting. So that means the shaft from the transfer case doesn't turn at all either, so basically the front differential is completely unused (and not moving) when 2WD is engaged. That's awesome. We're still carrying the extra dead weight (how much extra is it with 4WD?), but it's not moving, therefore not adding any friction for better fuel economy. Nice system. It's a very clever system. Systems with a center differential are always turning, which is not really needed on a truck. With this 'smart' transfer case, we have the best of both worlds IMO. Great. Thanks to all who patiently help answer my questions. Greatly appreciated
.
And thanks a lot for tha IWE video. It clearly shows where the IWEs are. Never heard of that system. Interesting. So that means the shaft from the transfer case doesn't turn at all either, so basically the front differential is completely unused (and not moving) when 2WD is engaged. That's awesome. We're still carrying the extra dead weight (how much extra is it with 4WD?), but it's not moving, therefore not adding any friction for better fuel economy. Nice system. It's a very clever system. Systems with a center differential are always turning, which is not really needed on a truck. With this 'smart' transfer case, we have the best of both worlds IMO. Great. Thanks to all who patiently help answer my questions. Greatly appreciated
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The following users liked this post:
Florida_F150 (07-07-2018)
07-07-2018, 09:36 AM
#49
Just read the entire section of the manual again (not the best written). Was reading the '2-speed automatic 4WD (don't know what the hell that is), but after that, it's the '4A' section, and it clearly states 4A is suitable for all 'on-road driving conditions', but only in normal and sport modes. So you were correct. Thank you for pointing that out. And with your testimonial, it's obviously okay to use it all the time. That is very good news to those who develop issues with the IWEs. Rather than risk damage, I'd just engage 4A until it's fixed, probably with a new check valve.
And thanks a lot for tha IWE video. It clearly shows where the IWEs are. Never heard of that system. Interesting. So that means the shaft from the transfer case doesn't turn at all either, so basically the front differential is completely unused (and not moving) when 2WD is engaged. That's awesome. We're still carrying the extra dead weight (how much extra is it with 4WD?), but it's not moving, therefore not adding any friction for better fuel economy. Nice system. It's a very clever system. Systems with a center differential are always turning, which is not really needed on a truck. With this 'smart' transfer case, we have the best of both worlds IMO. Great. Thanks to all who patiently help answer my questions. Greatly appreciated.
And thanks a lot for tha IWE video. It clearly shows where the IWEs are. Never heard of that system. Interesting. So that means the shaft from the transfer case doesn't turn at all either, so basically the front differential is completely unused (and not moving) when 2WD is engaged. That's awesome. We're still carrying the extra dead weight (how much extra is it with 4WD?), but it's not moving, therefore not adding any friction for better fuel economy. Nice system. It's a very clever system. Systems with a center differential are always turning, which is not really needed on a truck. With this 'smart' transfer case, we have the best of both worlds IMO. Great. Thanks to all who patiently help answer my questions. Greatly appreciated
.The "2-speed", I think they're just referring to the fact that the transfer case has both Hi and Lo gearing. Just like you'd say "I have a 2-speed transfer case" meaning it has Hi and Lo.