Hi all,

I was stuck in the snow today and I've noticed my 4WD mode does not
seem to function well. As I've never had to use it before on this jeep
I bought used, it's hard to me to tell which is fine and not fine.
Here are some symptoms:

1) there is not indicator saying I am in 4WD mode. Some search on the
internet suggest the the vacuum switch is dead. Is this switch only
linked to the light bulbs or does it affect the whole functionning of
the 4WD ?

2) I can feel when the jeep is in 4L but I don't feel much difference
between 2WD and 4H modes. Is this normal ?

3) after being in 4L, switching from N to 4H is hard. While driving in
2WD, there are no unusual noise. Acceleration in 4L is not smooth.

Any ideas ?

Thanks !

Lionel

 

On Sun, 18 Mar 2007 13:50:37 -0700, Lionel wrote:

> Hi all,
>
> I was stuck in the snow today and I've noticed my 4WD mode does not seem
> to function well. As I've never had to use it before on this jeep I
> bought used, it's hard to me to tell which is fine and not fine. Here
> are some symptoms:
>
> 1) there is not indicator saying I am in 4WD mode. Some search on the
> internet suggest the the vacuum switch is dead. Is this switch only
> linked to the light bulbs or does it affect the whole functionning of
> the 4WD ?
>
> 2) I can feel when the jeep is in 4L but I don't feel much difference
> between 2WD and 4H modes. Is this normal ?
>
> 3) after being in 4L, switching from N to 4H is hard. While driving in
> 2WD, there are no unusual noise. Acceleration in 4L is not smooth.
>
> Any ideas ?

You should make a habit of cycling through the 4WD options every few
months just to keep things greasy - like the front drive line.

Big cause of no light is a burned out bulb - but here's the easiest way
to check what is really happening.

Jack both front wheels off the ground with the rear wheels chocked. MAKE
SURE THE TRANSMISSION IS IN NEUTRAL AND RECHECK BEFORE DOING ANYTHING
WITH THE SHIFTER!! With the engine running, shift the transfer case to
2HI. Spin one front wheel and the other one should just sit there (I'm
pretty sure the 91 still had the axle disconnect). If both wheels spin
(usually in opposite direction), then reach under and try to turn the
front drive shaft. It should turn by hand. Now start the engine and
move the transfer case shift to the 4HI position. Turn the engine off and
check the front wheels again. Both should definitely spin if you spin
one. If only only one turns, you do have the axle disconnect and it
ain't working. You should NOT be able to turn the front drive shaft by
hand - if you can turn it, then the transfer case is not going into the
4WD mode. If you can't turn the drive shaft and only one front wheel
turns when you spin it, the problem is either the shift motor on the
front axle or a vacuum problem. If both front wheels spin but you can't
turn the drive shaft by hand, you are pretty certain to have a
functioning 4WD and it's either a burned out bulb, a wiring problem to
the switch or a bad switch. If the check shows a problem, it's likely
either a bad vacuum switch on the transfer case or bad vacuum lines from
that switch to the front axle.

--
Will Honea <whonea@yahoo.com>

 

On Sun, 18 Mar 2007 13:50:37 -0700, Lionel wrote:

> Hi all,
>
> I was stuck in the snow today and I've noticed my 4WD mode does not seem
> to function well. As I've never had to use it before on this jeep I
> bought used, it's hard to me to tell which is fine and not fine. Here
> are some symptoms:
>
> 1) there is not indicator saying I am in 4WD mode. Some search on the
> internet suggest the the vacuum switch is dead. Is this switch only
> linked to the light bulbs or does it affect the whole functionning of
> the 4WD ?
>
> 2) I can feel when the jeep is in 4L but I don't feel much difference
> between 2WD and 4H modes. Is this normal ?
>
> 3) after being in 4L, switching from N to 4H is hard. While driving in
> 2WD, there are no unusual noise. Acceleration in 4L is not smooth.
>
> Any ideas ?

You should make a habit of cycling through the 4WD options every few
months just to keep things greasy - like the front drive line.

Big cause of no light is a burned out bulb - but here's the easiest way
to check what is really happening.

Jack both front wheels off the ground with the rear wheels chocked. MAKE
SURE THE TRANSMISSION IS IN NEUTRAL AND RECHECK BEFORE DOING ANYTHING
WITH THE SHIFTER!! With the engine running, shift the transfer case to
2HI. Spin one front wheel and the other one should just sit there (I'm
pretty sure the 91 still had the axle disconnect). If both wheels spin
(usually in opposite direction), then reach under and try to turn the
front drive shaft. It should turn by hand. Now start the engine and
move the transfer case shift to the 4HI position. Turn the engine off and
check the front wheels again. Both should definitely spin if you spin
one. If only only one turns, you do have the axle disconnect and it
ain't working. You should NOT be able to turn the front drive shaft by
hand - if you can turn it, then the transfer case is not going into the
4WD mode. If you can't turn the drive shaft and only one front wheel
turns when you spin it, the problem is either the shift motor on the
front axle or a vacuum problem. If both front wheels spin but you can't
turn the drive shaft by hand, you are pretty certain to have a
functioning 4WD and it's either a burned out bulb, a wiring problem to
the switch or a bad switch. If the check shows a problem, it's likely
either a bad vacuum switch on the transfer case or bad vacuum lines from
that switch to the front axle.

--
Will Honea <whonea@yahoo.com>

 

On Sun, 18 Mar 2007 13:50:37 -0700, Lionel wrote:

> Hi all,
>
> I was stuck in the snow today and I've noticed my 4WD mode does not seem
> to function well. As I've never had to use it before on this jeep I
> bought used, it's hard to me to tell which is fine and not fine. Here
> are some symptoms:
>
> 1) there is not indicator saying I am in 4WD mode. Some search on the
> internet suggest the the vacuum switch is dead. Is this switch only
> linked to the light bulbs or does it affect the whole functionning of
> the 4WD ?
>
> 2) I can feel when the jeep is in 4L but I don't feel much difference
> between 2WD and 4H modes. Is this normal ?
>
> 3) after being in 4L, switching from N to 4H is hard. While driving in
> 2WD, there are no unusual noise. Acceleration in 4L is not smooth.
>
> Any ideas ?

You should make a habit of cycling through the 4WD options every few
months just to keep things greasy - like the front drive line.

Big cause of no light is a burned out bulb - but here's the easiest way
to check what is really happening.

Jack both front wheels off the ground with the rear wheels chocked. MAKE
SURE THE TRANSMISSION IS IN NEUTRAL AND RECHECK BEFORE DOING ANYTHING
WITH THE SHIFTER!! With the engine running, shift the transfer case to
2HI. Spin one front wheel and the other one should just sit there (I'm
pretty sure the 91 still had the axle disconnect). If both wheels spin
(usually in opposite direction), then reach under and try to turn the
front drive shaft. It should turn by hand. Now start the engine and
move the transfer case shift to the 4HI position. Turn the engine off and
check the front wheels again. Both should definitely spin if you spin
one. If only only one turns, you do have the axle disconnect and it
ain't working. You should NOT be able to turn the front drive shaft by
hand - if you can turn it, then the transfer case is not going into the
4WD mode. If you can't turn the drive shaft and only one front wheel
turns when you spin it, the problem is either the shift motor on the
front axle or a vacuum problem. If both front wheels spin but you can't
turn the drive shaft by hand, you are pretty certain to have a
functioning 4WD and it's either a burned out bulb, a wiring problem to
the switch or a bad switch. If the check shows a problem, it's likely
either a bad vacuum switch on the transfer case or bad vacuum lines from
that switch to the front axle.

--
Will Honea <whonea@yahoo.com>

 

Lionel wrote:
> Hi all,
>
> I was stuck in the snow today and I've noticed my 4WD mode does not
> seem to function well. As I've never had to use it before on this jeep
> I bought used, it's hard to me to tell which is fine and not fine.
> Here are some symptoms:
>
> 1) there is not indicator saying I am in 4WD mode. Some search on the
> internet suggest the the vacuum switch is dead. Is this switch only
> linked to the light bulbs or does it affect the whole functionning of
> the 4WD ?
>
> 2) I can feel when the jeep is in 4L but I don't feel much difference
> between 2WD and 4H modes. Is this normal ?
>
> 3) after being in 4L, switching from N to 4H is hard. While driving in
> 2WD, there are no unusual noise. Acceleration in 4L is not smooth.
>
> Any ideas ?
>
> Thanks !
>
> Lionel
>

I think your linkage could use some lubrication. It is open to the
elements down under there.

I am not sure where the 4x4 switch is on the 91, some are down on the
axle disconnect if the 91 has that. Passenger side at the back of the
tube. There are vacuum lines going there too that lock in the front
axle. The light doesn't mean much about 4x4 except that maybe the front
axle isn't hooked up. The shifter does the real work of getting into 4x4.

Could you spin the front tire?

Your other 'symptoms' sound normal. This part time 4x4 is only meant to
be used on snow covered roads or dirt.

In 4 low it acts like a jackrabbit. If you wind it up in 4 low on too
hard a surface, sometimes it won't want to come out and you have to
goose it spinning tires in reverse to loosen it up. That would be a 4
low to neutral shift though which should happen at about 2 mph.

4 high can be shifted in and out at an legal speed.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)

 

Lionel wrote:
> Hi all,
>
> I was stuck in the snow today and I've noticed my 4WD mode does not
> seem to function well. As I've never had to use it before on this jeep
> I bought used, it's hard to me to tell which is fine and not fine.
> Here are some symptoms:
>
> 1) there is not indicator saying I am in 4WD mode. Some search on the
> internet suggest the the vacuum switch is dead. Is this switch only
> linked to the light bulbs or does it affect the whole functionning of
> the 4WD ?
>
> 2) I can feel when the jeep is in 4L but I don't feel much difference
> between 2WD and 4H modes. Is this normal ?
>
> 3) after being in 4L, switching from N to 4H is hard. While driving in
> 2WD, there are no unusual noise. Acceleration in 4L is not smooth.
>
> Any ideas ?
>
> Thanks !
>
> Lionel
>

I think your linkage could use some lubrication. It is open to the
elements down under there.

I am not sure where the 4x4 switch is on the 91, some are down on the
axle disconnect if the 91 has that. Passenger side at the back of the
tube. There are vacuum lines going there too that lock in the front
axle. The light doesn't mean much about 4x4 except that maybe the front
axle isn't hooked up. The shifter does the real work of getting into 4x4.

Could you spin the front tire?

Your other 'symptoms' sound normal. This part time 4x4 is only meant to
be used on snow covered roads or dirt.

In 4 low it acts like a jackrabbit. If you wind it up in 4 low on too
hard a surface, sometimes it won't want to come out and you have to
goose it spinning tires in reverse to loosen it up. That would be a 4
low to neutral shift though which should happen at about 2 mph.

4 high can be shifted in and out at an legal speed.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)

 

Lionel wrote:
> Hi all,
>
> I was stuck in the snow today and I've noticed my 4WD mode does not
> seem to function well. As I've never had to use it before on this jeep
> I bought used, it's hard to me to tell which is fine and not fine.
> Here are some symptoms:
>
> 1) there is not indicator saying I am in 4WD mode. Some search on the
> internet suggest the the vacuum switch is dead. Is this switch only
> linked to the light bulbs or does it affect the whole functionning of
> the 4WD ?
>
> 2) I can feel when the jeep is in 4L but I don't feel much difference
> between 2WD and 4H modes. Is this normal ?
>
> 3) after being in 4L, switching from N to 4H is hard. While driving in
> 2WD, there are no unusual noise. Acceleration in 4L is not smooth.
>
> Any ideas ?
>
> Thanks !
>
> Lionel
>

I think your linkage could use some lubrication. It is open to the
elements down under there.

I am not sure where the 4x4 switch is on the 91, some are down on the
axle disconnect if the 91 has that. Passenger side at the back of the
tube. There are vacuum lines going there too that lock in the front
axle. The light doesn't mean much about 4x4 except that maybe the front
axle isn't hooked up. The shifter does the real work of getting into 4x4.

Could you spin the front tire?

Your other 'symptoms' sound normal. This part time 4x4 is only meant to
be used on snow covered roads or dirt.

In 4 low it acts like a jackrabbit. If you wind it up in 4 low on too
hard a surface, sometimes it won't want to come out and you have to
goose it spinning tires in reverse to loosen it up. That would be a 4
low to neutral shift though which should happen at about 2 mph.

4 high can be shifted in and out at an legal speed.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)

 

Hi all,

I didn't have a chance to check your advice since I am quite poor in
terms of tools to do the job but I am pretty sure there would have
been useful. I had to go for some oil changes and a couple of things
after being stuck again in the snow (you feel quite stupid to see your
4wd car needs some help while a regular car can do the job on a
standard parking lot covered by snow). It appeared one of the vacuum
lines was dead. The car is still at the shop for an alignment problem
I've noticed after my long drive from California to Maine ($$$ in
repairs ahead) but I should be good after that unless the Maine safety
inspection reveals something nasty.

Lionel


On Mar 18, 5:21 pm, Will Honea <who...@yahoo.com> wrote:
> On Sun, 18 Mar 2007 13:50:37 -0700, Lionel wrote:
> > Hi all,
>
> > I was stuck in the snow today and I've noticed my 4WD mode does not seem
> > to function well. As I've never had to use it before on this jeep I
> > bought used, it's hard to me to tell which is fine and not fine. Here
> > are some symptoms:
>
> > 1) there is not indicator saying I am in 4WD mode. Some search on the
> > internet suggest the the vacuum switch is dead. Is this switch only
> > linked to the light bulbs or does it affect the whole functionning of
> > the 4WD ?
>
> > 2) I can feel when the jeep is in 4L but I don't feel much difference
> > between 2WD and 4H modes. Is this normal ?
>
> > 3) after being in 4L, switching from N to 4H is hard. While driving in
> > 2WD, there are no unusual noise. Acceleration in 4L is not smooth.
>
> > Any ideas ?
>
> You should make a habit of cycling through the 4WD options every few
> months just to keep things greasy - like the front drive line.
>
> Big cause of no light is a burned out bulb - but here's the easiest way
> to check what is really happening.
>
> Jack both front wheels off the ground with the rear wheels chocked. MAKE
> SURE THE TRANSMISSION IS IN NEUTRAL AND RECHECK BEFORE DOING ANYTHING
> WITH THE SHIFTER!! With the engine running, shift the transfer case to
> 2HI. Spin one front wheel and the other one should just sit there (I'm
> pretty sure the 91 still had the axle disconnect). If both wheels spin
> (usually in opposite direction), then reach under and try to turn the
> front drive shaft. It should turn by hand. Now start the engine and
> move the transfer case shift to the 4HI position. Turn the engine off and
> check the front wheels again. Both should definitely spin if you spin
> one. If only only one turns, you do have the axle disconnect and it
> ain't working. You should NOT be able to turn the front drive shaft by
> hand - if you can turn it, then the transfer case is not going into the
> 4WD mode. If you can't turn the drive shaft and only one front wheel
> turns when you spin it, the problem is either the shift motor on the
> front axle or a vacuum problem. If both front wheels spin but you can't
> turn the drive shaft by hand, you are pretty certain to have a
> functioning 4WD and it's either a burned out bulb, a wiring problem to
> the switch or a bad switch. If the check shows a problem, it's likely
> either a bad vacuum switch on the transfer case or bad vacuum lines from
> that switch to the front axle.
>
> --
> Will Honea <who...@yahoo.com>- Hide quoted text -
>
> - Show quoted text -

 

Hi all,

I didn't have a chance to check your advice since I am quite poor in
terms of tools to do the job but I am pretty sure there would have
been useful. I had to go for some oil changes and a couple of things
after being stuck again in the snow (you feel quite stupid to see your
4wd car needs some help while a regular car can do the job on a
standard parking lot covered by snow). It appeared one of the vacuum
lines was dead. The car is still at the shop for an alignment problem
I've noticed after my long drive from California to Maine ($$$ in
repairs ahead) but I should be good after that unless the Maine safety
inspection reveals something nasty.

Lionel


On Mar 18, 5:21 pm, Will Honea <who...@yahoo.com> wrote:
> On Sun, 18 Mar 2007 13:50:37 -0700, Lionel wrote:
> > Hi all,
>
> > I was stuck in the snow today and I've noticed my 4WD mode does not seem
> > to function well. As I've never had to use it before on this jeep I
> > bought used, it's hard to me to tell which is fine and not fine. Here
> > are some symptoms:
>
> > 1) there is not indicator saying I am in 4WD mode. Some search on the
> > internet suggest the the vacuum switch is dead. Is this switch only
> > linked to the light bulbs or does it affect the whole functionning of
> > the 4WD ?
>
> > 2) I can feel when the jeep is in 4L but I don't feel much difference
> > between 2WD and 4H modes. Is this normal ?
>
> > 3) after being in 4L, switching from N to 4H is hard. While driving in
> > 2WD, there are no unusual noise. Acceleration in 4L is not smooth.
>
> > Any ideas ?
>
> You should make a habit of cycling through the 4WD options every few
> months just to keep things greasy - like the front drive line.
>
> Big cause of no light is a burned out bulb - but here's the easiest way
> to check what is really happening.
>
> Jack both front wheels off the ground with the rear wheels chocked. MAKE
> SURE THE TRANSMISSION IS IN NEUTRAL AND RECHECK BEFORE DOING ANYTHING
> WITH THE SHIFTER!! With the engine running, shift the transfer case to
> 2HI. Spin one front wheel and the other one should just sit there (I'm
> pretty sure the 91 still had the axle disconnect). If both wheels spin
> (usually in opposite direction), then reach under and try to turn the
> front drive shaft. It should turn by hand. Now start the engine and
> move the transfer case shift to the 4HI position. Turn the engine off and
> check the front wheels again. Both should definitely spin if you spin
> one. If only only one turns, you do have the axle disconnect and it
> ain't working. You should NOT be able to turn the front drive shaft by
> hand - if you can turn it, then the transfer case is not going into the
> 4WD mode. If you can't turn the drive shaft and only one front wheel
> turns when you spin it, the problem is either the shift motor on the
> front axle or a vacuum problem. If both front wheels spin but you can't
> turn the drive shaft by hand, you are pretty certain to have a
> functioning 4WD and it's either a burned out bulb, a wiring problem to
> the switch or a bad switch. If the check shows a problem, it's likely
> either a bad vacuum switch on the transfer case or bad vacuum lines from
> that switch to the front axle.
>
> --
> Will Honea <who...@yahoo.com>- Hide quoted text -
>
> - Show quoted text -

 

Hi all,

I didn't have a chance to check your advice since I am quite poor in
terms of tools to do the job but I am pretty sure there would have
been useful. I had to go for some oil changes and a couple of things
after being stuck again in the snow (you feel quite stupid to see your
4wd car needs some help while a regular car can do the job on a
standard parking lot covered by snow). It appeared one of the vacuum
lines was dead. The car is still at the shop for an alignment problem
I've noticed after my long drive from California to Maine ($$$ in
repairs ahead) but I should be good after that unless the Maine safety
inspection reveals something nasty.

Lionel


On Mar 18, 5:21 pm, Will Honea <who...@yahoo.com> wrote:
> On Sun, 18 Mar 2007 13:50:37 -0700, Lionel wrote:
> > Hi all,
>
> > I was stuck in the snow today and I've noticed my 4WD mode does not seem
> > to function well. As I've never had to use it before on this jeep I
> > bought used, it's hard to me to tell which is fine and not fine. Here
> > are some symptoms:
>
> > 1) there is not indicator saying I am in 4WD mode. Some search on the
> > internet suggest the the vacuum switch is dead. Is this switch only
> > linked to the light bulbs or does it affect the whole functionning of
> > the 4WD ?
>
> > 2) I can feel when the jeep is in 4L but I don't feel much difference
> > between 2WD and 4H modes. Is this normal ?
>
> > 3) after being in 4L, switching from N to 4H is hard. While driving in
> > 2WD, there are no unusual noise. Acceleration in 4L is not smooth.
>
> > Any ideas ?
>
> You should make a habit of cycling through the 4WD options every few
> months just to keep things greasy - like the front drive line.
>
> Big cause of no light is a burned out bulb - but here's the easiest way
> to check what is really happening.
>
> Jack both front wheels off the ground with the rear wheels chocked. MAKE
> SURE THE TRANSMISSION IS IN NEUTRAL AND RECHECK BEFORE DOING ANYTHING
> WITH THE SHIFTER!! With the engine running, shift the transfer case to
> 2HI. Spin one front wheel and the other one should just sit there (I'm
> pretty sure the 91 still had the axle disconnect). If both wheels spin
> (usually in opposite direction), then reach under and try to turn the
> front drive shaft. It should turn by hand. Now start the engine and
> move the transfer case shift to the 4HI position. Turn the engine off and
> check the front wheels again. Both should definitely spin if you spin
> one. If only only one turns, you do have the axle disconnect and it
> ain't working. You should NOT be able to turn the front drive shaft by
> hand - if you can turn it, then the transfer case is not going into the
> 4WD mode. If you can't turn the drive shaft and only one front wheel
> turns when you spin it, the problem is either the shift motor on the
> front axle or a vacuum problem. If both front wheels spin but you can't
> turn the drive shaft by hand, you are pretty certain to have a
> functioning 4WD and it's either a burned out bulb, a wiring problem to
> the switch or a bad switch. If the check shows a problem, it's likely
> either a bad vacuum switch on the transfer case or bad vacuum lines from
> that switch to the front axle.
>
> --
> Will Honea <who...@yahoo.com>- Hide quoted text -
>
> - Show quoted text -