Yeah I didn't see anything of significance in my testing. A few months ago on a drive I have done a lot that is about 300 miles, I drove 100 miles in 2H and averaged 24 MPG. Then I switched on 4A for another 100 miles. No obvious difference. It changed by .1 or .2, but that can be accounted for just through elevation and traffic.

It may have more of an impact in city driving since you are actively driving the front wheels with more power when taking off, but once you are moving, I think it's negligible.

It's nearly impossible unfortunately to know for sure without being able to control for more environmental factors. Weather changes, traffic changes, hitting more traffic lights, etc, are more likely to have a significant impact than 4A vs 2H.

 

If you will drive in 4a exclusively you'll eventually notice that it could be better.
It's not going to be huge but it is some, you add a bit of drag to the transfer case clutches and you have the front axle fully engaged at all times.

If your truck is leveled around 2" or more, you'll wear a hole in the boots sooner than later, but not within the first several months, it will still take time but less time than the cv boots not in motion.

Sounds like 4a and sport mode is a good choice for you if you're chirping the tires already.

 

unless there is a hub disconnect wouldn't the cv shaft and obviously boot be turning all the time?

 

The hub is locked by default.
Once the vehicle is started, vacuum will draw the IWE away from the hub, unlocking the hub.

In 4a and any 4x4 mode, vacuum is cut off allowing the IWE to relock to the hub.

 

Unless they have a 2022 or later F-150 with 4A where the front IWEs are no longer present.

 

Thank you. I've read some of the IWE/Hub threads for the new model but didn't realize the hub configuration has changed.

Disregard my incorrect comment above.

 

read a little about eiwe units on the 2021 and newer models

interesting I didn’t realize that they had such a contraption on there gm went a much different route and just stuck the cv shaft directly thru the hub splined in place. I guess there is a many ways to skin a cat.

 

The consequence of no hub disconnect.. is that the front differential, driveshaft and transfer case chain are turning all the time. The transfer chain itself will wear more in this new setup. That will be another noise to listen to down the road..


My Cherokee transfer cases chains in a similar setup are trouble after 70-80k.. You can use syn transfer case fluid and get more out of it.. but you really need 30k changes on the transfer case with the new ford setup. I think the ford transfer case chain is only 1" anyway.. so use low range a lot and spinning all the time they will need more maintenance..

 

I only mentioned it because I didn't think I saw OPs model year in here. What you said is correct for my truck, but may not be if theirs doesn't have the IWEs.

I was worried that I may have been misremembering it too, haha.

 

I didn't notice a difference on either of mine, though I didn't try too much I just put it in 4A and forget about it.

KISS. More traction = more control = more betterer.

I don't want to have to remember to change it to get the traction I want when those times arise. Be like, oh **** I can't make this 110* right turn out of the the neighborhood into traffic of people driving stupidly fast around the corner because I forgot to put it into 4A. nah, I'll just have the best one selected all time and always be in 4A