Update - NP231 Swap - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep Grand Cherokee & Commander Forums > ZJ Grand Cherokee Forum > Update - NP231 Swap

Spartan Locker Promo Running now @ ROCKRIDGE 4WD plus FREEG2 Disc Brake Conversion Kit for Jeep Wrangler YJ TJ LJ ChTJ Wrangler 4" Rough Country Suspension Lift Kits in

Reply
Unread 06-12-2013, 11:44 AM   #1
huntsducks70
Registered User
1998 ZJ 
 
Join Date: May 2013
Location: So Cal
Posts: 154
Update - NP231 Swap

so i got my driveshaft back last night, shortened, balanced and 2 new 1310s for $80 out the door. i installed from and rear DS and added a 1 1/2 qts of ATF to the tcase and the tranny and took her for a test drive. all i can say is that it is a 100% improvement over driving around in 4wd. the best thing is that i gained 3+ mpg during city driving. not sure if i will see an improvement on the highway, probably not though.

1998 5.2 with 249, i swapped in a 99 case from a 2000 cherokee, spline count and input shaft were a match, went in without a hitch.









huntsducks70 is offline   Reply With Quote Quick reply to this message
Unread 06-12-2013, 11:52 AM   #2
OldManTan
Registered User
1998 ZJ 
 
Join Date: Feb 2013
Location: Redlands, Ca
Posts: 285
ready to help me with mine?
hahah jk
congrats!
OldManTan is offline   Reply With Quote Quick reply to this message
Unread 06-12-2013, 11:53 AM   #3
dnuccio
Registered User
1995 ZJ 
 
Join Date: Jul 2012
Location: Phoenix, AZ
Posts: 3,484
theres no way you gained 3mpg. all the front axle components are still turning, causing the same power loss as full time 4wd does. to benefit fuel economy wise, you would need manual locking hubs to disengage the wheels from the rest of the axle. your gains are probably percieved.
__________________
Reliability is relative
R.I.P. Ratmonkey
dnuccio is offline   Reply With Quote Quick reply to this message
Unread 06-12-2013, 02:20 PM   #4
huntsducks70
Registered User
1998 ZJ 
 
Join Date: May 2013
Location: So Cal
Posts: 154
okay, thanks for setting me straight, so if it is not 3mpg, what did you observe when you drove MY jeep? bottom line, i gained the 3mpg (per the lie-o-meter) i am content with this figure and the gain observed is consistent, sorry if you did not experience the same.

oh, and thanks for breaking down the workings of a non full float front axle.
huntsducks70 is offline   Reply With Quote Quick reply to this message
Unread 06-12-2013, 02:24 PM   #5
huntsducks70
Registered User
1998 ZJ 
 
Join Date: May 2013
Location: So Cal
Posts: 154
Quote:
Originally Posted by OldManTan View Post
ready to help me with mine?
hahah jk
congrats!
i am no expert on the subject, but am willing to assist you with the swap, i could definitely get us through it, i am serious if you get the urge to tackle this.
huntsducks70 is offline   Reply With Quote Quick reply to this message
Unread 06-12-2013, 02:32 PM   #6
WhiteOut
Web Wheeler
 
WhiteOut's Avatar
1998 ZJ 
 
Join Date: Dec 2007
Posts: 8,204
He is right about the mileage. Hand calculating the mileage is going to show that there is not enough gain to measure (pretty much 0.5 MPG). All provided you drive exactly the same way as before with the exact same conditions.
WhiteOut is online now   Reply With Quote Quick reply to this message
Unread 06-12-2013, 02:45 PM   #7
dnuccio
Registered User
1995 ZJ 
 
Join Date: Jul 2012
Location: Phoenix, AZ
Posts: 3,484
Quote:
Originally Posted by WhiteOut View Post
He is right about the mileage. Hand calculating the mileage is going to show that there is not enough gain to measure (pretty much 0.5 MPG). All provided you drive exactly the same way as before with the exact same conditions.
thanks whiteout
__________________
Reliability is relative
R.I.P. Ratmonkey
dnuccio is offline   Reply With Quote Quick reply to this message
Unread 06-12-2013, 03:04 PM   #8
98ZJLTD
Registered User
1998 ZJ 
 
Join Date: Jul 2012
Location: Denver, Colorado
Posts: 384
Quote:
Originally Posted by huntsducks70 View Post
so i got my driveshaft back last night, shortened, balanced and 2 new 1310s for $80 out the door. i installed from and rear DS and added a 1 1/2 qts of ATF to the tcase and the tranny and took her for a test drive. all i can say is that it is a 100% improvement over driving around in 4wd. the best thing is that i gained 3+ mpg during city driving. not sure if i will see an improvement on the highway, probably not though.

1998 5.2 with 249, i swapped in a 99 case from a 2000 cherokee, spline count and input shaft were a match, went in without a hitch.
I'm getting ready to swap a 231 out of a 2000 xj into my 98 here in a couple weeks, was the linkage much of a hassle to get set up correctly? That's the only part of that project that's making me nervous at this point although I'm sure it won't be as big of deal as I'm thinking its gonna be.
__________________
98 ZJ Limited- NP231 swap, IRO 4.5 inch Springs, Hydro Shocks, IRO adjustable double shear track bar, JKS quick discos 33x12.50 Kumho Road Venture MT on 15x8 D windows with 3.75 inch BS

My build thread- [url]http://www.jeepforum.com/forum/f197/98zjltds-build-thread-1557637/[/url]
98ZJLTD is offline   Reply With Quote Quick reply to this message
Unread 06-12-2013, 03:10 PM   #9
huntsducks70
Registered User
1998 ZJ 
 
Join Date: May 2013
Location: So Cal
Posts: 154
i am going to agree to disagree. i understand all that hand calc stuff, most who confirm the results are within +/-.5mpg of the meter.

you guys may be correct when the delta is a 30/70 split, but my VC was dead and at 50/50 i am experiencing some great results with my 231
huntsducks70 is offline   Reply With Quote Quick reply to this message
Unread 06-12-2013, 03:18 PM   #10
huntsducks70
Registered User
1998 ZJ 
 
Join Date: May 2013
Location: So Cal
Posts: 154
Quote:
Originally Posted by 98ZJLTD View Post
I'm getting ready to swap a 231 out of a 2000 xj into my 98 here in a couple weeks, was the linkage much of a hassle to get set up correctly? That's the only part of that project that's making me nervous at this point although I'm sure it won't be as big of deal as I'm thinking its gonna be.
i agree as the linkage was a concern for me as well, but in all honesty, it was not that bad. i had my son hold the lever in its most reward position (4lo) and then i took up the slack in the linkage and tightened it up. no pop outs yet and i have done a couple nice 2wd drive burn outs (although they did not satisfy my 11 year old son) and no issue so far. i am keeping my fingers crossed.

let me know if you need more details or pics and i will do my best to assist.
huntsducks70 is offline   Reply With Quote Quick reply to this message
Unread 06-12-2013, 03:23 PM   #11
PolkaPower
Registered User
1998 ZJ 
 
Join Date: Aug 2011
Location: The Abyss, Italy
Posts: 16,508
You probably gained the mileage because you don't have a bad VC anymore not because you have 2wd. In working order the 96+ 249 is basically Rwd until the tires slip so it's not pushing power to the front like when the VC goes bad. You also lightened the Jeep by 30 lbs. Now you can fit more fat chicks in there
PolkaPower is offline   Reply With Quote Quick reply to this message
Unread 06-12-2013, 03:51 PM   #12
98ZJLTD
Registered User
1998 ZJ 
 
Join Date: Jul 2012
Location: Denver, Colorado
Posts: 384
Quote:
Originally Posted by huntsducks70 View Post

i agree as the linkage was a concern for me as well, but in all honesty, it was not that bad. i had my son hold the lever in its most reward position (4lo) and then i took up the slack in the linkage and tightened it up. no pop outs yet and i have done a couple nice 2wd drive burn outs (although they did not satisfy my 11 year old son) and no issue so far. i am keeping my fingers crossed.

let me know if you need more details or pics and i will do my best to assist.
Nice, sounds like It should be easier than I was thinking it was gonna be then. Did you change the plugs for the 4wd indicator on the vic? I can't decide if its worth the effort or not, my vic works fine (for now) and I kinda like having it but if I can manage to get my hands on 2wd cubby I might just go that route instead. I will definitely hit you up if I need anymore details, I'm feeling pretty solid about it at this point t though.
__________________
98 ZJ Limited- NP231 swap, IRO 4.5 inch Springs, Hydro Shocks, IRO adjustable double shear track bar, JKS quick discos 33x12.50 Kumho Road Venture MT on 15x8 D windows with 3.75 inch BS

My build thread- [url]http://www.jeepforum.com/forum/f197/98zjltds-build-thread-1557637/[/url]
98ZJLTD is offline   Reply With Quote Quick reply to this message
Unread 06-12-2013, 03:55 PM   #13
Rich93ZJ
Registered User
1993 ZJ 
 
Join Date: Sep 2012
Location: Richland, Ga
Posts: 455
Quote:
Originally Posted by PolkaPower View Post
You probably gained the mileage because you don't have a bad VC anymore not because you have 2wd. In working order the 96+ 249 is basically Rwd until the tires slip so it's not pushing power to the front like when the VC goes bad. You also lightened the Jeep by 30 lbs. Now you can fit more fat chicks in there
^^THIS^^......You probably went from 9mpg to 12mpg
Rich93ZJ is offline   Reply With Quote Quick reply to this message
Unread 06-12-2013, 05:38 PM   #14
huntsducks70
Registered User
1998 ZJ 
 
Join Date: May 2013
Location: So Cal
Posts: 154
Quote:
Originally Posted by PolkaPower View Post
You also lightened the Jeep by 30 lbs. Now you can fit more fat chicks in there
i stopped dating your sister, so no worries there.
huntsducks70 is offline   Reply With Quote Quick reply to this message
Unread 06-12-2013, 05:39 PM   #15
huntsducks70
Registered User
1998 ZJ 
 
Join Date: May 2013
Location: So Cal
Posts: 154
Quote:
Originally Posted by Rich93ZJ View Post
^^THIS^^......You probably went from 9mpg to 12mpg
damn, you must have a ****ty running rig, mine kicks ***.
huntsducks70 is offline   Reply With Quote Quick reply to this message
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.
Note: All free e-mails have been banned due to mis-use. (Yahoo, Gmail, Hotmail, etc.)
Don't have a non-free e-mail address? Click here for a solution: Manual Account Creation
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.


Thread Tools






Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.