WJ Drive systems, or, What is QuadraDrive?

Jeep has a confusing naming system for their available drive systems.

2wd WJs are not covered here - this is a really a 4wd blog. 

QuadraDrive

       AWD/N/4Lo NP247 TCase

       Varilocks factory "limited slips" in both axles

          I've quoted "limited slip" because these units, like a Gov Loc, will lock up.

          They're very good when properly driven. I have yet to find a decent Youtube video tho.
SelecTrac

       2wd, 4Part Time, 4Full Time, N, 4Lo - NP242 tcase. 

       Select units came with Varilocks on both diffs, but most were open in both diffs
QuadraTrac

       AWD/N/4Lo NP247 TCase

       Both diffs are open

Axleshafts are not interchangeable between Varilock and open differentials.
If you plan on going to an ARB or Detroit locker (or lunchbox locker), Varilock owners will need to swap out both axleshafts to open differential units in each axle undergoing this upgrade. IF you're thinking lunchbox locker, you'd need to change the carrier, making it prohibitively expensive - you might as well do a real locker.

I have an Aussie lunchbox locker in the back of my QuadraTrac truck and I get outdriven by QuadraDrive trucks.

Plan accordingly.  :)

JOATJeep's modifications

Current specs

• 16 mpg mixed (calculated, does not include CAI)
• San Diego has crappy CA gas, and hills. Lots and lots of hills.
• As good as 18 on the highway at decent speeds (speed limit +)
• 32" OEM tire (added 1mpg)
• stock gears
• Rear Aussie lunchbox locker

Engine (order of install starts at bottom)

• "Cold air" Intake kit
• Cannot recommend this modification
• Read my Amazon review 
• Best reduction I've seen is between 2-4 degrees (Scanguage II)
• Generally running 20-30 degrees HOTTER than stock everywhere but on the highway.
• MPG seems to have increased but then the increase goes away, need to confirm with fill, but could be as much as 1-2mpg. I rely on gallons added/miles driven as for all mpg values I post.
• Talked to Airaid, of course they're owned by K&N. It's all making sense now. Here's K&N's version's HP
• Throttle body
• Doesn't seem to have done much
• Crisper throttle response. Added after everything else, I can't say it made much of a difference. Easier to bark the tires from a stop I guess.
• Bosch V3 4 hole injectors (for the 4.7) 
• Stronger low and end midrange. The first mod I would recommend
• EVIC no longer accurate
• 2002 HO cams, intake, and fuel injectors
• NOTE - Bosch 4-hole injectors are much better than the HO injectors
• Decent upgrade, FlashPaq required to get best results
• 3" cat back exhaust
• my truck is a 2-cat truck to begin with, so no 3rd cat to delete or deal with (CA, delete would be bad)
• Y pipe goes into 3" beautifully thanks to Ed Hanson exhaust (San Diego)
• Ran Kolak 3" exhaust - it's decent, sounds good. 
• Didn't fit with custom long arm
• Replaced with 3" with Model TBD Magnaflow. Louder than Kolak, but fits with long arm, dumps in front of the axle. It's great. Went flanged to allow tcase removal (not necessary, but can help)
• SuperChips Flashpaq
• Change ECU tire size to fix speedo
• 87 MPG tune
• Improves shifts
• Revs more smoothly to redline
• Running 91 performance tune
• MPG is better than 87 MPG tune
• In Miles/$, it's about the same/slightly better when Premium is <= $0.20 gallon more than 87
• Power is definitely better
• Shifts are crisper, much less retard, now pulls to redline

Drivetrain (order of install starts at bottom)

• NP242HD SelecTrac tcase (2wd, 4Hi, 4FullTime, N, 4Lo) swapped in, replaced NP247 (AWD,  N, 4Lo). See 
• Increased MPG by about 1mpg
• 4Hi is much more predictable than AWD when bombing around curves offroad
• 4FullTime will probably never be used - it's basically an open diff between front and rear axles. Useless.
• Direct bolt-in IF I would have had the rear driveshaft. 32 spline shaft (vs 27), and different length, so it's critical to get the shaft
• Because of that, used IRO SYE and a Tatton's driveshaft (bought through IRO)
• Aussie locker
• Spartans had issues with shearing teeth. Lots of noise on the interweb about that.
• Aussie had nearly no issues found 
• Was installed with NP247 in the truck, worked great. 
• Transmission rebuild at around 120K. Tremendously disappointed with the tranny life on these. Check valve wore out and transmission lost pressure, fragged the whole thing
• Used TransGo rebuild shift kit parts to repair check valve galling into aluminum housing.  With the SuperChips, the resistor is not used
• Did not install the shift springs as wasn't looking for a hotrod shifts

Body (order of install starts at bottom)

• Rough Country Swaybar disconnects
• The only Rough Country anything making it onto my truck. :)
• ScanGauge II
• Fantastic little tool. Reads and resets codes, MPG, instant MPG, intake temps, etc, etc.
• Fixed left front pin on the front seat frame (welding involved)
• Custom long arm, 0.25" walled tubing. 
• 3 link in front
• maintains rear 3-link/A-arm style
• Design means no more rear upper A-arm bushings wearing out quickly
• Handles fantastically on pavement
• Currently shock-limited travel
• JK Rubicon wheels