Are the front axles and drive shaft "engaged" (ie: being turned by the
front wheels) while in 2WD?

If so, is it a worthwhile investment, *gas milage wise*, to get a
setup that includes manual locking hubs?

TIA

PS: I've just finished my second full tank of gas.
The first one I was *trying* to get good milage and got 14.x MPG.
(A/C ON most of the time, little highway time.)
The second I was lead footing it all the time and got 13.x MPG.
(A/C OFF most of the time, a lot more highway time this time.)

I was a bit surprised. I thought I was going to hit single digits :/


I plan on installing a washable air filter (K&N or the one of the
other brands now available), and am thinking about replacing the
axle/xfr case fluids with "Royal Purple" lube. Anyone have experience
with this stuff?

I also found a tire size calc
(http://www.discounttire.com/dtcs/infoTireMath.dos)
that indicated that my oversized tires (235/75-15) cause my speedo to
read about 4% under actual.

Is the odometer affected to the same degree?

And, lastly <g>, I've lost my reference to this: My Cherokee is an XJ,
right?

(Again, TIA)

....

 

The answers to your questions depend on the year, and transfer case. If you
have "full time four wheel drive" aka SelecTrac, then your axles are engaged
all the time and there is nothing you can do about it. If you have "part
time four wheel drive" aka CommandTrac, then you may have a "passenger side
axle disconnect". With CommandTrac, you have "2H 4H N 4L" on the transfer
case shifter. With SelecTrac there is an additional selection. If you have
CommandTrac, look under the vehicle, at the middle of the passenger side
front axle tube, for a squarish box, that encloses a vacuum control. It
will have vacuum and electrical lines going to it. If you have this, then
one of your front axles is disconnected in two wheel drive. This keeps the
drive shaft from turning, but does not prevent all energy losses due to
friction.

There is a front locking hub kit, available for the Wranglers. If you have
the CommandTrac system, with or without the vacuum disconnect, then it
should fit your Cherokee, because they use essentially the same front axle.
Last year, I would have said that the cost was not worth it, but with the
price of fuel going up, and no end really in sight, who can say? If you are
interested in this conversion, look on the www.4wd.com web site for "WarnŽ
Front Lockout Hub Conversion Kit". The parts are about a thousand dollars,
plus new brake disks and the cost of labor. You will probably do a front
brake job too, while you are installing the conversion.

Earle

"noneyabusiness" <me@you.com> wrote in message
news:our5n1p9fk34ob7nrdkvpk8aej91vmr3ie@4ax.com...
> Are the front axles and drive shaft "engaged" (ie: being turned by the
> front wheels) while in 2WD?
>
> If so, is it a worthwhile investment, *gas milage wise*, to get a
> setup that includes manual locking hubs?
>
> TIA
>
> PS: I've just finished my second full tank of gas.
> The first one I was *trying* to get good milage and got 14.x MPG.
> (A/C ON most of the time, little highway time.)
> The second I was lead footing it all the time and got 13.x MPG.
> (A/C OFF most of the time, a lot more highway time this time.)
>
> I was a bit surprised. I thought I was going to hit single digits :/
>
>
> I plan on installing a washable air filter (K&N or the one of the
> other brands now available), and am thinking about replacing the
> axle/xfr case fluids with "Royal Purple" lube. Anyone have experience
> with this stuff?
>
> I also found a tire size calc
> (http://www.discounttire.com/dtcs/infoTireMath.dos)
> that indicated that my oversized tires (235/75-15) cause my speedo to
> read about 4% under actual.
>
> Is the odometer affected to the same degree?
>
> And, lastly <g>, I've lost my reference to this: My Cherokee is an XJ,
> right?
>
> (Again, TIA)
>
> ...

 

The answers to your questions depend on the year, and transfer case. If you
have "full time four wheel drive" aka SelecTrac, then your axles are engaged
all the time and there is nothing you can do about it. If you have "part
time four wheel drive" aka CommandTrac, then you may have a "passenger side
axle disconnect". With CommandTrac, you have "2H 4H N 4L" on the transfer
case shifter. With SelecTrac there is an additional selection. If you have
CommandTrac, look under the vehicle, at the middle of the passenger side
front axle tube, for a squarish box, that encloses a vacuum control. It
will have vacuum and electrical lines going to it. If you have this, then
one of your front axles is disconnected in two wheel drive. This keeps the
drive shaft from turning, but does not prevent all energy losses due to
friction.

There is a front locking hub kit, available for the Wranglers. If you have
the CommandTrac system, with or without the vacuum disconnect, then it
should fit your Cherokee, because they use essentially the same front axle.
Last year, I would have said that the cost was not worth it, but with the
price of fuel going up, and no end really in sight, who can say? If you are
interested in this conversion, look on the www.4wd.com web site for "WarnŽ
Front Lockout Hub Conversion Kit". The parts are about a thousand dollars,
plus new brake disks and the cost of labor. You will probably do a front
brake job too, while you are installing the conversion.

Earle

"noneyabusiness" <me@you.com> wrote in message
news:our5n1p9fk34ob7nrdkvpk8aej91vmr3ie@4ax.com...
> Are the front axles and drive shaft "engaged" (ie: being turned by the
> front wheels) while in 2WD?
>
> If so, is it a worthwhile investment, *gas milage wise*, to get a
> setup that includes manual locking hubs?
>
> TIA
>
> PS: I've just finished my second full tank of gas.
> The first one I was *trying* to get good milage and got 14.x MPG.
> (A/C ON most of the time, little highway time.)
> The second I was lead footing it all the time and got 13.x MPG.
> (A/C OFF most of the time, a lot more highway time this time.)
>
> I was a bit surprised. I thought I was going to hit single digits :/
>
>
> I plan on installing a washable air filter (K&N or the one of the
> other brands now available), and am thinking about replacing the
> axle/xfr case fluids with "Royal Purple" lube. Anyone have experience
> with this stuff?
>
> I also found a tire size calc
> (http://www.discounttire.com/dtcs/infoTireMath.dos)
> that indicated that my oversized tires (235/75-15) cause my speedo to
> read about 4% under actual.
>
> Is the odometer affected to the same degree?
>
> And, lastly <g>, I've lost my reference to this: My Cherokee is an XJ,
> right?
>
> (Again, TIA)
>
> ...

 

The answers to your questions depend on the year, and transfer case. If you
have "full time four wheel drive" aka SelecTrac, then your axles are engaged
all the time and there is nothing you can do about it. If you have "part
time four wheel drive" aka CommandTrac, then you may have a "passenger side
axle disconnect". With CommandTrac, you have "2H 4H N 4L" on the transfer
case shifter. With SelecTrac there is an additional selection. If you have
CommandTrac, look under the vehicle, at the middle of the passenger side
front axle tube, for a squarish box, that encloses a vacuum control. It
will have vacuum and electrical lines going to it. If you have this, then
one of your front axles is disconnected in two wheel drive. This keeps the
drive shaft from turning, but does not prevent all energy losses due to
friction.

There is a front locking hub kit, available for the Wranglers. If you have
the CommandTrac system, with or without the vacuum disconnect, then it
should fit your Cherokee, because they use essentially the same front axle.
Last year, I would have said that the cost was not worth it, but with the
price of fuel going up, and no end really in sight, who can say? If you are
interested in this conversion, look on the www.4wd.com web site for "WarnŽ
Front Lockout Hub Conversion Kit". The parts are about a thousand dollars,
plus new brake disks and the cost of labor. You will probably do a front
brake job too, while you are installing the conversion.

Earle

"noneyabusiness" <me@you.com> wrote in message
news:our5n1p9fk34ob7nrdkvpk8aej91vmr3ie@4ax.com...
> Are the front axles and drive shaft "engaged" (ie: being turned by the
> front wheels) while in 2WD?
>
> If so, is it a worthwhile investment, *gas milage wise*, to get a
> setup that includes manual locking hubs?
>
> TIA
>
> PS: I've just finished my second full tank of gas.
> The first one I was *trying* to get good milage and got 14.x MPG.
> (A/C ON most of the time, little highway time.)
> The second I was lead footing it all the time and got 13.x MPG.
> (A/C OFF most of the time, a lot more highway time this time.)
>
> I was a bit surprised. I thought I was going to hit single digits :/
>
>
> I plan on installing a washable air filter (K&N or the one of the
> other brands now available), and am thinking about replacing the
> axle/xfr case fluids with "Royal Purple" lube. Anyone have experience
> with this stuff?
>
> I also found a tire size calc
> (http://www.discounttire.com/dtcs/infoTireMath.dos)
> that indicated that my oversized tires (235/75-15) cause my speedo to
> read about 4% under actual.
>
> Is the odometer affected to the same degree?
>
> And, lastly <g>, I've lost my reference to this: My Cherokee is an XJ,
> right?
>
> (Again, TIA)
>
> ...

 

Yes, the later model XJs and the TJs have the front propeller shaft
spinning all the time, no matter if you are in 4wd or not.
__________________________________________________ _________
tw

71 Bill Stroppe Baja Bronco
03 TJ Rubicon - Rubicon Express 4.5"
01 XJ Sport

There is a very fine line between "hobby" and "mental illness."
-- Dave Barry

Pronunciation: 'jEp
Function: noun
Date: 1940

Etymology: from g. p. (G= 'Government' P= '80 inch wheelbase')
A small general-purpose motor vehicle with 80-inch wheelbase,
1/4-ton capacity, and four-wheel drive used by the U.S. army in
World War II.

(Please remove the OBVIOUS to reply by email)
__________________________________________________ _________


noneyabusiness wrote:
> Are the front axles and drive shaft "engaged" (ie: being turned by the
> front wheels) while in 2WD?
>
> If so, is it a worthwhile investment, *gas milage wise*, to get a
> setup that includes manual locking hubs?
>
> TIA
>
> PS: I've just finished my second full tank of gas.
> The first one I was *trying* to get good milage and got 14.x MPG.
> (A/C ON most of the time, little highway time.)
> The second I was lead footing it all the time and got 13.x MPG.
> (A/C OFF most of the time, a lot more highway time this time.)
>
> I was a bit surprised. I thought I was going to hit single digits :/
>
>
> I plan on installing a washable air filter (K&N or the one of the
> other brands now available), and am thinking about replacing the
> axle/xfr case fluids with "Royal Purple" lube. Anyone have experience
> with this stuff?
>
> I also found a tire size calc
> (http://www.discounttire.com/dtcs/infoTireMath.dos)
> that indicated that my oversized tires (235/75-15) cause my speedo to
> read about 4% under actual.
>
> Is the odometer affected to the same degree?
>
> And, lastly <g>, I've lost my reference to this: My Cherokee is an XJ,
> right?
>
> (Again, TIA)
>
> ...

 

Yes, the later model XJs and the TJs have the front propeller shaft
spinning all the time, no matter if you are in 4wd or not.
__________________________________________________ _________
tw

71 Bill Stroppe Baja Bronco
03 TJ Rubicon - Rubicon Express 4.5"
01 XJ Sport

There is a very fine line between "hobby" and "mental illness."
-- Dave Barry

Pronunciation: 'jEp
Function: noun
Date: 1940

Etymology: from g. p. (G= 'Government' P= '80 inch wheelbase')
A small general-purpose motor vehicle with 80-inch wheelbase,
1/4-ton capacity, and four-wheel drive used by the U.S. army in
World War II.

(Please remove the OBVIOUS to reply by email)
__________________________________________________ _________


noneyabusiness wrote:
> Are the front axles and drive shaft "engaged" (ie: being turned by the
> front wheels) while in 2WD?
>
> If so, is it a worthwhile investment, *gas milage wise*, to get a
> setup that includes manual locking hubs?
>
> TIA
>
> PS: I've just finished my second full tank of gas.
> The first one I was *trying* to get good milage and got 14.x MPG.
> (A/C ON most of the time, little highway time.)
> The second I was lead footing it all the time and got 13.x MPG.
> (A/C OFF most of the time, a lot more highway time this time.)
>
> I was a bit surprised. I thought I was going to hit single digits :/
>
>
> I plan on installing a washable air filter (K&N or the one of the
> other brands now available), and am thinking about replacing the
> axle/xfr case fluids with "Royal Purple" lube. Anyone have experience
> with this stuff?
>
> I also found a tire size calc
> (http://www.discounttire.com/dtcs/infoTireMath.dos)
> that indicated that my oversized tires (235/75-15) cause my speedo to
> read about 4% under actual.
>
> Is the odometer affected to the same degree?
>
> And, lastly <g>, I've lost my reference to this: My Cherokee is an XJ,
> right?
>
> (Again, TIA)
>
> ...

 

Yes, the later model XJs and the TJs have the front propeller shaft
spinning all the time, no matter if you are in 4wd or not.
__________________________________________________ _________
tw

71 Bill Stroppe Baja Bronco
03 TJ Rubicon - Rubicon Express 4.5"
01 XJ Sport

There is a very fine line between "hobby" and "mental illness."
-- Dave Barry

Pronunciation: 'jEp
Function: noun
Date: 1940

Etymology: from g. p. (G= 'Government' P= '80 inch wheelbase')
A small general-purpose motor vehicle with 80-inch wheelbase,
1/4-ton capacity, and four-wheel drive used by the U.S. army in
World War II.

(Please remove the OBVIOUS to reply by email)
__________________________________________________ _________


noneyabusiness wrote:
> Are the front axles and drive shaft "engaged" (ie: being turned by the
> front wheels) while in 2WD?
>
> If so, is it a worthwhile investment, *gas milage wise*, to get a
> setup that includes manual locking hubs?
>
> TIA
>
> PS: I've just finished my second full tank of gas.
> The first one I was *trying* to get good milage and got 14.x MPG.
> (A/C ON most of the time, little highway time.)
> The second I was lead footing it all the time and got 13.x MPG.
> (A/C OFF most of the time, a lot more highway time this time.)
>
> I was a bit surprised. I thought I was going to hit single digits :/
>
>
> I plan on installing a washable air filter (K&N or the one of the
> other brands now available), and am thinking about replacing the
> axle/xfr case fluids with "Royal Purple" lube. Anyone have experience
> with this stuff?
>
> I also found a tire size calc
> (http://www.discounttire.com/dtcs/infoTireMath.dos)
> that indicated that my oversized tires (235/75-15) cause my speedo to
> read about 4% under actual.
>
> Is the odometer affected to the same degree?
>
> And, lastly <g>, I've lost my reference to this: My Cherokee is an XJ,
> right?
>
> (Again, TIA)
>
> ...

 

Yes, you have an XJ More information of Jeep models is available here:
http://www.ajeepthing.com/models/jeep_models.asp

Well....depending on your driving route and habits you might get 14 mpg.
In strictly suburban driving I get 17 in my WJ, in general driving
(suburban, open road, highway) it goes up to about 20. At reasonable
highway speeds it will get 24. I've never driven it any real distance at 55
mph as driving that slowly is dangerous.

I am a strong proponent of Synthetic fluids, they have superior lubricating
and cleaning capacities, especially in extremes, but have never used any
Royal Purple Brand products.

I read/watched a few of the posted tests on Royal Purple's web-site and was
not impressed. The routine appears to be that several changes are made such
as fluids (+ a tune up) or fluids (+ new exhaust components) or thermal
imaging (+ a floor fan is running).

An honest test would only change the test fluids and not other factors that
are also known to increase engine power and decrease temperature.

As for K&N (& clones) filters you will find that people either swear by them
or swear at them, no one who uses them is indifferent.

You should be aware that K&N make more power by lowering the resistance in
the air intake just like the advertisements claim. What they don't tell you
is they have lower resistance because they only filter the very large
particles, all the fine ones (that get trapped by a paper filter) go right
through. I am sure someone will supply links to pix of K&N protected
engines.....


>
> PS: I've just finished my second full tank of gas.
> The first one I was *trying* to get good milage and got 14.x MPG.
> (A/C ON most of the time, little highway time.)
> The second I was lead footing it all the time and got 13.x MPG.
> (A/C OFF most of the time, a lot more highway time this time.)
>
> I was a bit surprised. I thought I was going to hit single digits :/
>
>
> I plan on installing a washable air filter (K&N or the one of the
> other brands now available), and am thinking about replacing the
> axle/xfr case fluids with "Royal Purple" lube. Anyone have experience
> with this stuff?
>

 

Yes, you have an XJ More information of Jeep models is available here:
http://www.ajeepthing.com/models/jeep_models.asp

Well....depending on your driving route and habits you might get 14 mpg.
In strictly suburban driving I get 17 in my WJ, in general driving
(suburban, open road, highway) it goes up to about 20. At reasonable
highway speeds it will get 24. I've never driven it any real distance at 55
mph as driving that slowly is dangerous.

I am a strong proponent of Synthetic fluids, they have superior lubricating
and cleaning capacities, especially in extremes, but have never used any
Royal Purple Brand products.

I read/watched a few of the posted tests on Royal Purple's web-site and was
not impressed. The routine appears to be that several changes are made such
as fluids (+ a tune up) or fluids (+ new exhaust components) or thermal
imaging (+ a floor fan is running).

An honest test would only change the test fluids and not other factors that
are also known to increase engine power and decrease temperature.

As for K&N (& clones) filters you will find that people either swear by them
or swear at them, no one who uses them is indifferent.

You should be aware that K&N make more power by lowering the resistance in
the air intake just like the advertisements claim. What they don't tell you
is they have lower resistance because they only filter the very large
particles, all the fine ones (that get trapped by a paper filter) go right
through. I am sure someone will supply links to pix of K&N protected
engines.....


>
> PS: I've just finished my second full tank of gas.
> The first one I was *trying* to get good milage and got 14.x MPG.
> (A/C ON most of the time, little highway time.)
> The second I was lead footing it all the time and got 13.x MPG.
> (A/C OFF most of the time, a lot more highway time this time.)
>
> I was a bit surprised. I thought I was going to hit single digits :/
>
>
> I plan on installing a washable air filter (K&N or the one of the
> other brands now available), and am thinking about replacing the
> axle/xfr case fluids with "Royal Purple" lube. Anyone have experience
> with this stuff?
>

 

Yes, you have an XJ More information of Jeep models is available here:
http://www.ajeepthing.com/models/jeep_models.asp

Well....depending on your driving route and habits you might get 14 mpg.
In strictly suburban driving I get 17 in my WJ, in general driving
(suburban, open road, highway) it goes up to about 20. At reasonable
highway speeds it will get 24. I've never driven it any real distance at 55
mph as driving that slowly is dangerous.

I am a strong proponent of Synthetic fluids, they have superior lubricating
and cleaning capacities, especially in extremes, but have never used any
Royal Purple Brand products.

I read/watched a few of the posted tests on Royal Purple's web-site and was
not impressed. The routine appears to be that several changes are made such
as fluids (+ a tune up) or fluids (+ new exhaust components) or thermal
imaging (+ a floor fan is running).

An honest test would only change the test fluids and not other factors that
are also known to increase engine power and decrease temperature.

As for K&N (& clones) filters you will find that people either swear by them
or swear at them, no one who uses them is indifferent.

You should be aware that K&N make more power by lowering the resistance in
the air intake just like the advertisements claim. What they don't tell you
is they have lower resistance because they only filter the very large
particles, all the fine ones (that get trapped by a paper filter) go right
through. I am sure someone will supply links to pix of K&N protected
engines.....


>
> PS: I've just finished my second full tank of gas.
> The first one I was *trying* to get good milage and got 14.x MPG.
> (A/C ON most of the time, little highway time.)
> The second I was lead footing it all the time and got 13.x MPG.
> (A/C OFF most of the time, a lot more highway time this time.)
>
> I was a bit surprised. I thought I was going to hit single digits :/
>
>
> I plan on installing a washable air filter (K&N or the one of the
> other brands now available), and am thinking about replacing the
> axle/xfr case fluids with "Royal Purple" lube. Anyone have experience
> with this stuff?
>