front axle 4x actuator

i've heard you can lock the actuator permenently to bypas the vacuum system.
has anyone done this? does anyone know the efects of this -ie:front shaft spins freely/does it lock the diff?

Yeah, it'll be permanintly locked. No shifting out of 4WD.

i thaught the lever on the floor had 2 funktions
1.) shift t-case
2.) lock front axle ???



with just the axle locked sepratly would the t-case turn the front shaft/


either way the axle is locked so no pavement?

You can permanantly lock the passenger side front axle on a disco front end with no issue. You then have a front end just like later XJ's/TJ's, etc without the disco. No effect on street driving, it's still 2wd but both front axles now spin all the time. The T-case is still in 2wd and not applying power to the front end. The easy way is to remove the shift motor, take it apart, and shim the fork so it keeps the collar in locked position. The other way is to get rid of the disco motor and just use a later model one piece shaft. You need to remove the carrier and install a special seal in the axle tube. The part # is floating on this board somewhere.

The handle on the floor controls the range of the tcase. When you put in 4WD, it activates a vacuum switch on the back of the case that moves the shift fork on the disconnect to lock the front axle. If you permanantly lock the axle or put in a one piece shaft, then you trash all the vaccuum lines and plug it at the source.

Waterhammer said:

Yeah, it'll be permanintly locked. No shifting out of 4WD.

Click to expand...

SPOBI !!!

so... in 2wd the front wheels wouldn't be locked because the drive shaft could turn freely alowing the tires to turn at differant rates around corners?

then... in 4wd the drive shaft would be engaged no longer alowing the tires to turn independantly?


please bere with me as i am new to the jeep world...
...well the stuff that differs from my AMC Eagle anyway

Unless you have a front locker the front axle still differentiates even though the axle is "engaged" the only thing that's going on is the front ds is spinning at the same rate as the axle....but has no effect because its "freewheeling" inside the t-case while in 2wd,it has absolutely no effect on drive ability on the street in 2wd...gas mileage suffers a little,thats all.

I recommend looking at a parts diagram of your case or take one apart to get a full understanding of whats going on here.

sorry if my explination was lacking. sounds like im on the same page

it just looked like the proper fix would be spendyer than prefered

and the t case will be coming apart soon... ill be teaching myself how to installan sye kit b4 i lift
any suggestions on manufacturer?

This is what I run...
http://www.jbconversions.com/pages/

outlander said:

gas mileage suffers a little,thats all.
.

Click to expand...

hardly .1 mpg though, so don't start thinkin this thing actually saves mileage, its more like yard-age.

go about 3/4 of the way down this page and it shows a write-up on permanently engaging the front right axleshaft. nto hard, no effect on street driving unless you have a full lock (lincoln locker, spool that type of thing) all lock-rights and those types will be fine with this 'fix'
http://www.comancheclub.com/forums/viewtopic.php?t=2001&postdays=0&postorder=asc&start=30

anybody know what year range that used the vacuum disconnect for? when did they stop using it?

I've got a buddy with a dodge pickup and he's having problems with it engaging into 4x4. He keeps taking it in and having vaccuum lines fixed. It works for a bit and then it stops working again. Maybe we will pull his apart and see if it is a similar idea as the d30. thanks for the writup.

I may be mistaken, but the vacu-disco front axle was used from '84 to '90 or '91, I think. I too have the issue with the vacuum system...and have shimmed the vac motor to keep my son's '88 XJ permanently "locked". I do wonder, though, is the collar slide meant to be engaged all the time? Will it wear? Reason I ask is that a "permi-lok" sold recommends it for off-road use only (not for daily driver). Wear on the collar or shaft ends is the only reason I can think of for not using the permi-lok all the time for a daily driver. Anyone with additional insight, please respond!

Thanks in advance.

azranger said:

I've got a buddy with a dodge pickup and he's having problems with it engaging into 4x4. He keeps taking it in and having vaccuum lines fixed. It works for a bit and then it stops working again. Maybe we will pull his apart and see if it is a similar idea as the d30. thanks for the writup.

Click to expand...

I had an 86' dodge pickup with the vacuum actuated shifter and it kept goin out on me, so i bought a posi lok for it and it worked every time.

here is some of the stuff that I found there are links inside the thread and much more info on it. If you check some YJ forums you'll most likely get more answers, but here is some of what I found
http://www.jeepsunlimited.com/forums/showthread.php?t=789129

yeah, you could just not worry abotu it and install a rusty's posi-lok cable (or any other brand) i think RE has them as well.

i was wondering about just using a non-disconnect right side shaft and gutting that stupid disconnect, but the seals are different from the two models i beleive.