Unlock hubs in 94 Cherokee

I've never used four wheel drive on a highway.
God Bless America, ßill O|||||||O
http://www.billhughes.com/

Mike Romain wrote:
>
> Crap Bill, I can just see someone doing 65 mph and in order to shift
> having to stop on the highway and go backward against 70 mph traffic to
> shift to 2WD. LOL! Too funny....
>
> Mike

Lucky you.....

We need it on the highway up here which is when the Jeep 'shift on the
fly' system is so nice.

Mike

"L.W.(ßill) Hughes III" wrote:
>
> I've never used four wheel drive on a highway.
> God Bless America, ßill O|||||||O
> http://www.billhughes.com/
>
> Mike Romain wrote:
> >
> > Crap Bill, I can just see someone doing 65 mph and in order to shift
> > having to stop on the highway and go backward against 70 mph traffic to
> > shift to 2WD. LOL! Too funny....
> >
> > Mike

This has nothing to do with the hubs. On an older transfer case the
slider that engages and disengages 4wd can get a little roughed up. In
this case disengaging while driving can be a little noisy, especially if
you have some windup due to tire pressures being off so that the
effective diameters of the tires are different. Stopping and reversing
unloads the coupling allowing it to disengage smoothly.

wrote:

> I just purchased a 2nd-hand 1994 Cherokee with the 5-speed manual,
> part-time 4WD tranny. The previous owner told me that you needed to
> back it up to unlock the hubs after having it in 4WD. I had to do this
> for my 88 Trooper. But I haven't seen anything in the Jeep owner's
> manual about backing up to unlock the hubs.
>
> Do I need to back to unlock hubs, or not?
>
> thanks,
>
> Tom
>

"Mike Romain" > wrote in message
...
> He doesn't have a locking front end, it is on all the time.
>
> Even with the old vacuum lock, shifting is by a lever on the floor. If
> this lever on the floor will shift to 2 wheel drive, you are freaking
> 'IN' 2 wheel drive no matter if the front axle is a vacuum release,
> permanent locked, or manually locked!
>
But Mike, he was told to go in reverse to allow the mechanism to unlock. I
was thinking he has the system like that in the YJ. It turns out he has the
system that is like the TJ.




> There is no such thing as having to go into reverse to 'unlock' front
> hubs or axles period! That cannot happen on "ANY" Jeep!
>

This is not entirely true. Well, it is true in theory. That is there is no
requirement, but we all know that the YJ's front axle can balk at unlocking
when the tcase lever is moved back to 2WD, the work-around for this
balkiness is to back up a few yards.


> Once the shifter has moved to 2 wheel drive, the front driveshaft is no
> longer connected to the drivetrain, therefore there can be no 'binding
> up'. The older vacuum collar cannot 'bind up' when the driveshaft is
> not connected....
>
> Now if your gear shift won't come out of 4x4, then yes, you do have to
> maybe back up to shift the transfer case.
>

I follow that, but what I have always seen is that the collar sticks.
Backing up a little solves this. Having read about the lever binding up, my
CJ has never had this trouble, so I assumed that any binding in a YJ would
be the fork or the collar on the axle.



> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
>
> Jeff Strickland wrote:
> >
> > The hubs lock through a vacuum mechanism. There is a collar of sorts
that
> > slides over two splined shafts to connect them, this collar moves on
command
> > of a vacuum system. Sometimes the shafts and collar can bind, and going
in
> > reverse will release the bind and allow the collar to move back to its
home
> > position. This is not in the manual because it is not "required". It is
> > helpful though. You can also release the binding, if present, by
changing
> > the load on the drive train, you can do this by letting off of the gas
and
> > turning the steering wheel from side to side.
> >
> > If you shift out of 4WD, and can hear the resulting clunk from the
movement
> > of the collar, then you do not have to do anything else. In theory, all
you
> > need do is shift out of 4WD, and eventually the vacuum system will pull
the
> > collar back to its home position. In practice, the collar can stick and
the
> > remedy is to try going backwards for a few feet.
> >
> > > wrote in message
> > ups.com...
> > > I just purchased a 2nd-hand 1994 Cherokee with the 5-speed manual,
> > > part-time 4WD tranny. The previous owner told me that you needed to
> > > back it up to unlock the hubs after having it in 4WD. I had to do
this
> > > for my 88 Trooper. But I haven't seen anything in the Jeep owner's
> > > manual about backing up to unlock the hubs.
> > >
> > > Do I need to back to unlock hubs, or not?
> > >
> > > thanks,
> > >
> > > Tom
> > >

"Steve" > wrote in message
...
> Incorrect. You won't find the vacuum disconnect axle on a 1994 Cherokee.
> Last model year for that was 1991 for XJ/MJ and 1995 for YJ. The hubs on
> a 94 Cherokee are permanently connected straight through the axles to
> the differential.

Just like the TJ?

I thought the Cherokee in '94 would have the same system as the YJ of the
same year.

Our Transfer cases are likely to bind coming out of four wheel
drive on good traction, because your AMC 20 and My nine inch do not
exactly match ratios with our front ends. Something Mike doesn't
experience having both front and rear Danas.
God Bless America, ßill O|||||||O
http://www.billhughes.com/

Jeff Strickland wrote:
>
> But Mike, he was told to go in reverse to allow the mechanism to unlock. I
> was thinking he has the system like that in the YJ. It turns out he has the
> system that is like the TJ.
>
> This is not entirely true. Well, it is true in theory. That is there is no
> requirement, but we all know that the YJ's front axle can balk at unlocking
> when the tcase lever is moved back to 2WD, the work-around for this
> balkiness is to back up a few yards.

The confusion seems to be between the 4x4 and a vacuum slider or the
dash light on the YJ's and early Cherokee. The light only means the
axle hasn't released yet.

If the vehicle is in 2 wheel drive via the shifter and the slider
doesn't want to unlock, you need to floor it up to say 3000 rpm, then
let off the gas fast. This will boost the vacuum to the max and make
the slider move and turn off the dash light. I guess you could also
stop and back up to boost the vacuum because stopped is high vacuum but
that isn't really practical if you are doing 65 mph or needed for that
matter.

You can still safely drive at any speed or terrain with the front slider
'stuck' so the 4x4 light stays on but have the shifter in 2 wheel
drive. On my 88 Cherokee that means about 3 mpg on the highway
difference. My vacuum slider has been stuck 'on' for a while now and I
haven't been physically able to crawl under to play with the hoses.

It is common for me to need to back up after coming out a trail before I
can shift the transfer case out of 4 low in my CJ7. I have high
traction so my Dana 300 can get pretty wound up sometimes. I then need
to spin the tires. I still leave my hubs locked for half a year
though.....

None of this has anything to do with the front axle or hub locks though,
they are a totally different animal and are completely different than
the 4x4 shift.

Mike

Jeff Strickland wrote:
>
> "Mike Romain" > wrote in message
> ...
> > He doesn't have a locking front end, it is on all the time.
> >
> > Even with the old vacuum lock, shifting is by a lever on the floor. If
> > this lever on the floor will shift to 2 wheel drive, you are freaking
> > 'IN' 2 wheel drive no matter if the front axle is a vacuum release,
> > permanent locked, or manually locked!
> >
> But Mike, he was told to go in reverse to allow the mechanism to unlock. I
> was thinking he has the system like that in the YJ. It turns out he has the
> system that is like the TJ.
>
> > There is no such thing as having to go into reverse to 'unlock' front
> > hubs or axles period! That cannot happen on "ANY" Jeep!
> >
>
> This is not entirely true. Well, it is true in theory. That is there is no
> requirement, but we all know that the YJ's front axle can balk at unlocking
> when the tcase lever is moved back to 2WD, the work-around for this
> balkiness is to back up a few yards.
>
> > Once the shifter has moved to 2 wheel drive, the front driveshaft is no
> > longer connected to the drivetrain, therefore there can be no 'binding
> > up'. The older vacuum collar cannot 'bind up' when the driveshaft is
> > not connected....
> >
> > Now if your gear shift won't come out of 4x4, then yes, you do have to
> > maybe back up to shift the transfer case.
> >
>
> I follow that, but what I have always seen is that the collar sticks.
> Backing up a little solves this. Having read about the lever binding up, my
> CJ has never had this trouble, so I assumed that any binding in a YJ would
> be the fork or the collar on the axle.
>
> > Mike
> > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> > 88 Cherokee 235 BFG AT's
> >
> > Jeff Strickland wrote:
> > >
> > > The hubs lock through a vacuum mechanism. There is a collar of sorts
> that
> > > slides over two splined shafts to connect them, this collar moves on
> command
> > > of a vacuum system. Sometimes the shafts and collar can bind, and going
> in
> > > reverse will release the bind and allow the collar to move back to its
> home
> > > position. This is not in the manual because it is not "required". It is
> > > helpful though. You can also release the binding, if present, by
> changing
> > > the load on the drive train, you can do this by letting off of the gas
> and
> > > turning the steering wheel from side to side.
> > >
> > > If you shift out of 4WD, and can hear the resulting clunk from the
> movement
> > > of the collar, then you do not have to do anything else. In theory, all
> you
> > > need do is shift out of 4WD, and eventually the vacuum system will pull
> the
> > > collar back to its home position. In practice, the collar can stick and
> the
> > > remedy is to try going backwards for a few feet.
> > >
> > > > wrote in message
> > > ups.com...
> > > > I just purchased a 2nd-hand 1994 Cherokee with the 5-speed manual,
> > > > part-time 4WD tranny. The previous owner told me that you needed to
> > > > back it up to unlock the hubs after having it in 4WD. I had to do
> this
> > > > for my 88 Trooper. But I haven't seen anything in the Jeep owner's
> > > > manual about backing up to unlock the hubs.
> > > >
> > > > Do I need to back to unlock hubs, or not?
> > > >
> > > > thanks,
> > > >
> > > > Tom
> > > >

Jeff Strickland wrote:
> "Steve" > wrote ...
>
>>Incorrect. You won't find the vacuum disconnect axle on a 1994 Cherokee.
>>Last model year for that was 1991 for XJ/MJ and 1995 for YJ. The hubs on
>>a 94 Cherokee are permanently connected straight through the axles to
>>the differential.
>
> Just like the TJ?
>
> I thought the Cherokee in '94 would have the same system as the YJ of the
> same year.

Yup, they ditched the problematic disconnect in '92 in the XJ coil link
suspensions. They didn't bother investing the same change for the YJ's
leaf-sprung Dana 30 knowing it was a dead duck soon to be replaced by
the XJ coil link Dana 30 in the TJ.

Steve
http://xjeep.dyndns.org

That still has absolutely 'nothing' to do with unlocking the front
hubs!!!!

That is the t-case binding up. It happens on my dana set up too because
of the high traction muds I run.

I thought the real bad set was the 410/411 splits on some of them.

Mike

"L.W.(ßill) Hughes III" wrote:
>
> Our Transfer cases are likely to bind coming out of four wheel
> drive on good traction, because your AMC 20 and My nine inch do not
> exactly match ratios with our front ends. Something Mike doesn't
> experience having both front and rear Danas.
> God Bless America, ßill O|||||||O
> http://www.billhughes.com/
>
> Jeff Strickland wrote:
> >
> > But Mike, he was told to go in reverse to allow the mechanism to unlock. I
> > was thinking he has the system like that in the YJ. It turns out he has the
> > system that is like the TJ.
> >
> > This is not entirely true. Well, it is true in theory. That is there is no
> > requirement, but we all know that the YJ's front axle can balk at unlocking
> > when the tcase lever is moved back to 2WD, the work-around for this
> > balkiness is to back up a few yards.

Jeff Strickland wrote:
>
> "Mike Romain" > wrote in message
> ...
>
> > There is no such thing as having to go into reverse to 'unlock' front
> > hubs or axles period! That cannot happen on "ANY" Jeep!
> >
>
> This is not entirely true. Well, it is true in theory. That is there is no
> requirement, but we all know that the YJ's front axle can balk at unlocking
> when the tcase lever is moved back to 2WD, the work-around for this
> balkiness is to back up a few yards.

The best work around it to hit 3000 rpm and let off the gas for maximum
vacuum.

Going in reverse has 0 effect except at the idle point when the vacuum
comes up because the transfer case is already in 2 wheel drive so the
driveshaft is loose already.

Mike