If you remove the front differential and driveshaft you might see a slight increase in MPGs due to less weight it's carrying but definitely not worth doing if you're doing it just to save. When you drive it and it's not in 4WD you're just driving in 2WD simply put.

The transmission doesn't know much of a difference if there's no power going from the transfer case to the wheels or not.

 

I wouldn't think the trans would matter because it is only connected through the transfer case. I am referring to reduced rolling resistance by the wheels not having to spin the frt diff gears and frt prop shaft back to the transfer case.

 

Doesn't the D use a sealed front bearing? If so it should be fine without anything in the middle. You would basically destroy the CV shaft taking it apart to use it like that. You could reassemble it all but you would need new inner and outer boot.

 

It's been a couple years since I had mine out, but trying to remember back I recall that end of the CV shaft being pretty beefy. It definitely gave me the impression that it was structurally important.

That hub assembly was designed with the assumption that the CV shaft and hub nut would be in place. I'll admit that I don't know for sure, but sealed or not, I doubt that it has the strength without them to hold together long term. I still have visions of the front wheels simply falling right off sooner or later if it was driven without that in place.

Given that I was able to find a used front diff for only $190 and replacement can be done in an afternoon by a moderately experienced shadetree mechanic, I'm sticking with my opinion that this particular mod has far more downside than upside.....

 

the loss attributed to pushing the front driveline is very minimal, as stated you will see more gains from the decrease in weight of the vehicle than from the reduction in rolling resistance

 

Like everyone else said, MPG gain would barely even be noticeable. If you're car has AWD capability without being able to unlock the hubs/front shafts, like the Ds, you will get less MPGs in 2WD than in AWD but again a very small difference.

If you can find a used diff. from a bone yard and get that all ready to go and be installed, then you only have to take the front apart once. On the other hand, rebuilding a diff. is something I'd let an experienced shop do to get the gear meshing just right so you don't have backlash or whining noises.

 

And even that is how much? About the weight of throwing a 10 year old in the passenger seat? How many people get concerned about dramatic mpg swings when letting a passenger get in?

Very minimal......

 

Exactly my point on why I said don't do it if it's just for the hell of it. Usually if it ain't broke, don't fix it. This is one of those cases where you're going to spend more time and effort taking everything apart and putting it back together than you'll ever see in MPGs.

 

Well, It sounds like nobody has done it before, seems alot of speculation and no tried and true results, and I don't have extra $200.00+ laying around right now, and my plan does not cost anything, right now. So I will try it and let you know how it works out.

 

If you're saying nobody has rebuilt a diff. before, it's something I'd never do myself, I want a specialized shop to do it once and do it right. You can do it yourself to make it work, but later on it will probably get damaged quicker and you might have a really annoying whine/humming sound coming from it.