How do my hubs disengage?

[90Xjay]

OK, school is in session and I am ready to learn. This is my first jeep 4X4(90 Cherokee) I have been told that my XJ has a Dana 30 front axle and a 35 rear(with factory tow hitch, I thought it might have been a 44 but I have been told not)
The thing works fine, goes in and comes out of 4wheel drive great.
I want to understand how my hubs disengage. There is no vacuum line or any thing on the axle on either side where a disconnect would be. Believe me I have looked at this thing a long time. I had a previous post about why when I have the vehicle on stands and spin the LF tire the front shaft turns. Do my hubs stay in all the time and the case does all of the work?
I really want to understand my set-up.
thanks to all and Merry Christmas!!

Mark

 

[jay79cj7]

There is a vacuum disconnect on the axle. It disconnects the passenger side axle so the differential is not connected to the wheel on that side. Because its an open differential, no torque on the passenger side means that no power is transferred to the driver's side. I don't know if the driveshaft is disconnected at the transfer case or not.

This place is a great place to ask questions. I have learned a HUGE amount just by reading most of the posts on a daily basis.

 

[MudderChuck]

If your Xj has a part time/full time type transfer NP242, it likely doesn´t have a axle disconnect. Or a later model NP 231.
The axle disconnect on the XJ and YJ´s is typically on one axle and used with the NP231, when there. Halfway down the right axle, diconnects one axle shaft (slides in and out of a sleeve). The transfer disconnects the driveshaft.
Differential (without limited slip, ratchet or locked differential) works in three directions. But is biased (works the best) in the direction with the least drag (the one that turns the easiest). Unhook one leg, there is little drag, unhook two legs and there is almost no drag, most of the pieces just sit there.
The NP 242 (full time/part time) is said to have less drag. They decided they didn´t need the axle disconnect anymore. Or it could be harmfull to the transfer, if the axle didn´t engauge, when in 4 full or 4 partime. (have heard both theories). Engineers desided it was unecessary or more trouble than it was worth.

www.howstuffworks.com , has some good explanations and sometimes some good graphics.

 

[Bounty__Hunter]

Last year for the D44 in an XJ was '89, so you're late. You may have the Chrysler 8.25", they replaced the D44 in the tow package, if the receiver is factory.

Not all XJ's have the vacuum disconnect on the front axle. If you do, it'll be on the passenger side of the front axle between the differential and the coil spring, with two or three vacuum lines running to it.

The hubs on your XJ are a sealed, non-maintenance hub. You can not grease them or dissassemble them, and they must be repaced if they get any play to the tune of $125 each.

If you have no vacuum disconnect, there is no unlocking of hubs or axleshafts in your front axle. Shifting the transfer case to 2wd no longer sends power to the front driveshaft, but both front hubs and axle shafts stay connected to the front driveshaft via your open front differential.

 

[MudderChuck]

Basic 4X

Do I hold the record yet for the longest post?

 

[90Xjay]

TJ Help

Outstanding information!



Thank you all very much.
I have read so much about the vacuum disconnect on the front causing trouble, and after installing my Rusty's 3" lift last week, I became very familiar with my front axle, because I replaced the upper control arm bushings and I know that there is no disconnect on my axle. There are some interesting designs with differential and case combonations.
If I am not mistaken, my rear diff had had a "Dana" stamp somewhere, but a friend said it definatly was not a 44, so I just deduced it was a 35. I had read a post somewhere about the Cherokee being labled the most capable stock off-road vehicle when it was introduced and I can see why. I love this thing and want to keep and enjoy it for a long time.

 

[Bounty__Hunter]

Look on the differential gussets on the rear diff, it should read '35c'.

 

[90Xjay]

Bounty Hunter,
It sure does. I cleaned off a small area where you said it would be.
Well at least that is settled. Now if I can figure out how this &*%# Rusty's rear brake line extension is supposed to fit. This is the worst thing that Rusty's has ever sent me. It is just not a good bolt on bracket for this model. I'll more than likely end up getting a longer brake hose and be done with it.

thanks again!!

 

[XJNick]

I too have a strange brake line bracket from Rusty's. Haven't gotten around to installing it though :roll:

Merry Christmas :mrgreen:
-Nick :!:

 

[90Xjay]

Nick,

Look here http://www.4x4wire.com/jeep/tech/brakes/xjhoseext02/

For a better deal for more brake line play. That thing from Rusty's will not work and makes you bend and bend on your rear line, which can make it weak. I do not know how they expect it to work, my instructions say to unbolt the old bracket and replace with the new one. My bracket is welded to the frame and then there is the matter of the swaybar being about 1/2 and inch away. I will opt for the hose replacement, my brakes could use a good bleed anyway!!
Thanks and God Bless all!!