Caught a show earlier today that got me thinking.
Seems there's a vacuum operated device on the Dodges from the 1990's that disconnects the front axles from the differential when you're not in 4WD.
(My truck is an 08 so it has IFS.)
Is there some type of disconnect in my truck or are the front wheels always spinning the front diff whether I'm in 4WD or not?

If there is, where is it? & how does it work?

 

Oops, forgot to mention, I'm asking this from a mileage perspective, and wondering if it has automatic locking hubs. (The first ones of those didn't last too long.)

 

I'm pretty sure they use an electronic locking hub, which disengages the front wheels from the axles when in 2wd.

 

Should have auto-locking hubs.... Which should disengage it

 

Guys I dont think there is anything the disengage the CV shafts. I believe my truck anyway always has the front end turning. Disengaging hubs where big in the 90's but most people went away from it by the 2000's.

 

Nope it spins all the time. There are kits (at least for the 2500 and 3500) for manual hubs that disengage. Saves 1-2 mpg in real world testing

 

This is as far as I understand it - it disconnects in the front diff, and the transfer case.

So in 2wd your wheels and and axle shaft's are spinning (cv joints and all), but your front drive shaft won't be spinning.

 

Your front cv shafts are connected to your front wheels and are splined. Consider them permanently attatched with no unlocking availablities. If your front wheels are in rotaion, the cv's are rotating, so whenever you drive(whether in 2wd or 4wd) they are always rotating. Same goes for your front diff. It is always rotating as the cv shafts are connected to that as well.
What controls these is your transfercase. Your transfercase is what engages and disengages the power to the front diff.
2wd: CV shafts, front diff are all rotation due to being in contact with the ground
4wd: they are rotating due to engine power forcing them.

 

Ahh, so a levelling kit would still be damaging in 2wd. Gotcha