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Jeep Wrangler YJ
YJ Build Threads & Member's Rides
My '94 Hunter Green “No Compromises" Build
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<blockquote data-quote="machoheadgames" data-source="post: 428144" data-attributes="member: 18789"><p>Following the exhaust replacement, I decided to delete the problematic vacuum CAD setup from my front axle. Mine actually hadn't worked in years. My suspension was too tall and the vacuum hoses always came off the motor, and even when they did stay in place, the actuation of the motor was very inconsistent, like most YJs. Rather than even begin to consider repairing that system, I opted to go with the TJ/XJ one-piece axle swap.</p><p></p><p>Many people opt for the posi-lock or perma-lock kits. These work fine, get the job done, but the functionality wasn't what I wanted. The <strong>posi-lock </strong>kit includes a cable that switches the vacuum actuated setup to now be manually controlled by the driver. One benefit is that this allows for the driver to operate in a simulated 2Lo mode, by putting the transfer case in 4Lo and not engaging the front axle with the cable. Kind of cool, but the rest of the posi-lock details are cons to me. It has a giant red knob on the end of the cable that I really don't want on my non-red dash. It requires drilling a large hole in the firewall for the cable. It requires the driver to do the work every time, which I don't want to do. It can be finicky to operate. The <strong>perma-lock</strong> kit is basically a simulation of the TJ axle shaft swap. It locks the front passenger axle shafts together permanently, and can not be unlocked. The benefit to this is easier install than the TJ setup, since you don't have to remove the front carrier, install a special seal, etc. All you have to do is open the CAD, replace the cover with the permanently locked CAD cover, and go. Pretty simple, my issue with it was that it keeps the two separate shafts and permanently locks them. I feel it is stronger to have a one-piece axle shaft. </p><p></p><p>T<strong>he TJ/XJ Setup:</strong></p><p>Essentially the one piece axle swap from a TJ eliminates the two piece axle shafts from the YJ front axle. The parts needed are as follows:</p><p>-TJ/XJ passenger side front axle shaft (1996 and up are best for the larger u-joints!)</p><p>-TJ/XJ driver side axle shaft (only needed if seeking 1996+ - please don't get the larger u-joint shaft on one side and leave the other side stock! Nothing is more hack job than mismatched axle u-joint sizes).</p><p>-Napa 11800 axle seal (to go in passenger side of diff)</p><p>-Chrysler J8134473 Transfer Case Switch (for a TJ/XJ, it is electronic and replaces the old vacuum switch to keep the 4X4 light functional)</p><p>-18AWG wire (black is best to match stock)</p><p>-Delphi 2-Pin Male Weatherpack Plug with Male Terminals (typically male terminals go in female plugs but for this job, male needs to be used in a male plug)</p><p>-G2 Axle Block Off Plate (can just reuse stock CAD if desired, I wanted the cleaner look of a flat plate).</p><p>-New Cork Gasket for Block Off Plate</p><p>-Gear Oil</p><p></p><p><strong>The Conversion Process:</strong></p><p></p><p>The swap was pretty easy, but time consuming. Here are the steps:</p><p></p><p>-Jack up front end, set on jack stands, remove front wheels</p><p>-Remove front brake calipers and pull off rotors</p><p>-Undo front axle cotter pins and remove axle nuts to separate axle shafts from unit bearings</p><p>-Open up the CAD (Have a bucket ready, gear oil will drain out)</p><p>-Remove diff cover (Have a bigger bucket ready, even more gear oil will drain out)</p><p>-Remove Bearing caps to differential, remembering where each bolt goes and keeping caps in the proper orientation to reinstall them exactly the same way later</p><p>-Remove intermediate axle shaft by sliding out to passenger end of axle</p><p>-Install Napa Seal in passenger side of differential - NOTE - the axle tube is not machined for a seal. The Napa seal is the perfect OD for the axle tube and perfect ID for the axle shaft. It will theoretically pound all the way down the axle if you don't stop, so make sure you stop at the point where it rides on the machined portion of the axle shaft.</p><p>-Swap out driver side seal too since you're in there</p><p>-Install new axle shafts</p><p>-Button up the Diff and CAD</p><p>-Install unit bearings, torque unit bearing axle shaft nuts to 175 ft-lbs</p><p>-reinstall brakes and wheels</p><p>-Remove all the old vacuum crap out to the transfer case and engine. </p><p></p><p><strong>The 4X4 Light...</strong></p><p></p><p>Some people would say "I know when I'm in 4WD, I don't need no stinkin' light." While I don't necessarily disagree with the truth behind that statement, I like things to work as intended. For that reason I chose to rework the 4X4 light circuit to keep it working properly.</p><p></p><p>The factory 4X4 light on 92-95 YJs with the electronic gauges is pretty simple. The light always has fused power with the key is in the ignition. The light is controlled by the ground circuit. The light's ground runs out to the factory 4X4 switch mounted at the CAD. The second wire at the CAD carries the lamp ground out to the grounding point. When the Jeep is put in 4WD, the forks in the transfer case push a button on the 4-port vacuum switch, which connects engine vacuum to the CAD. The vacuum at the CAD motor then slides the CAD fork over, pushing the button on the switch. This connects the two wires together, and the lamp is then grounded and illuminates.</p><p></p><p>When you do the TJ axle swap, you get rid of this setup. The way the TJs and XJs have their light work from the factory is similar, except the wiring goes to the transfer case. The switch I listed is installed where the factory 4-port vacuum switch is on a YJ, and shifting into 4WD pushes the button on that switch, and the lamp is then grounded just like the front axle setup. The only process to making the lamp work is extending the wires to where they reach the transfer case, installing the switch I listed, and crimping on the Weatherpack plug I listed which then plugs into the switch. It is seriously easy as can be. Wrap any wiring in loom to protect it and zip tie it to the other transmission looms to keep it safe.</p><p></p><p>The end result is that when you put the Jeep in 4Hi or 4Lo, so long as the internals of the transfer case move properly, the 4X4 light on the dash will illuminate to reinforce the shift you made. It will shut off when transfer case is in neutral.</p><p></p><p>Overall I am very pleased with this one, I consider it OEM+. It is how the Jeep should have come from the factory, it works, no issues, complaints, etc. So much more reliable than the vacuum mess and it's nice to remove the clump of vacuum tubes and never have to worry about 4WD leaving you stranded.</p><p></p><p><strong>Pictures:</strong></p><p></p><p>Here you can see the finished front axle, no vacuum tubes, no wiring, and no gigantic flying saucer of a vacuum motor mounted to the axle. Much cleaner.</p><p></p><p>[ATTACH]116948[/ATTACH]</p><p></p><p>Here is the TJ transfer case switch, with my extended wiring ran to it.</p><p></p><p>[ATTACH]116949[/ATTACH]</p><p></p><p>Here is the vacuum tubing at the intake manifold. From the factory, This port tees off to feed the 4WD and the vacuum operated heater entry door. I repurposed this to be for the heater only, now that I have no need for vacuum 4WD. Works flawlessly.</p><p></p><p>[ATTACH]116950[/ATTACH]</p></blockquote><p></p>
[QUOTE="machoheadgames, post: 428144, member: 18789"] Following the exhaust replacement, I decided to delete the problematic vacuum CAD setup from my front axle. Mine actually hadn't worked in years. My suspension was too tall and the vacuum hoses always came off the motor, and even when they did stay in place, the actuation of the motor was very inconsistent, like most YJs. Rather than even begin to consider repairing that system, I opted to go with the TJ/XJ one-piece axle swap. Many people opt for the posi-lock or perma-lock kits. These work fine, get the job done, but the functionality wasn't what I wanted. The [B]posi-lock [/B]kit includes a cable that switches the vacuum actuated setup to now be manually controlled by the driver. One benefit is that this allows for the driver to operate in a simulated 2Lo mode, by putting the transfer case in 4Lo and not engaging the front axle with the cable. Kind of cool, but the rest of the posi-lock details are cons to me. It has a giant red knob on the end of the cable that I really don't want on my non-red dash. It requires drilling a large hole in the firewall for the cable. It requires the driver to do the work every time, which I don't want to do. It can be finicky to operate. The [B]perma-lock[/B] kit is basically a simulation of the TJ axle shaft swap. It locks the front passenger axle shafts together permanently, and can not be unlocked. The benefit to this is easier install than the TJ setup, since you don't have to remove the front carrier, install a special seal, etc. All you have to do is open the CAD, replace the cover with the permanently locked CAD cover, and go. Pretty simple, my issue with it was that it keeps the two separate shafts and permanently locks them. I feel it is stronger to have a one-piece axle shaft. T[B]he TJ/XJ Setup:[/B] Essentially the one piece axle swap from a TJ eliminates the two piece axle shafts from the YJ front axle. The parts needed are as follows: -TJ/XJ passenger side front axle shaft (1996 and up are best for the larger u-joints!) -TJ/XJ driver side axle shaft (only needed if seeking 1996+ - please don't get the larger u-joint shaft on one side and leave the other side stock! Nothing is more hack job than mismatched axle u-joint sizes). -Napa 11800 axle seal (to go in passenger side of diff) -Chrysler J8134473 Transfer Case Switch (for a TJ/XJ, it is electronic and replaces the old vacuum switch to keep the 4X4 light functional) -18AWG wire (black is best to match stock) -Delphi 2-Pin Male Weatherpack Plug with Male Terminals (typically male terminals go in female plugs but for this job, male needs to be used in a male plug) -G2 Axle Block Off Plate (can just reuse stock CAD if desired, I wanted the cleaner look of a flat plate). -New Cork Gasket for Block Off Plate -Gear Oil [B]The Conversion Process:[/B] The swap was pretty easy, but time consuming. Here are the steps: -Jack up front end, set on jack stands, remove front wheels -Remove front brake calipers and pull off rotors -Undo front axle cotter pins and remove axle nuts to separate axle shafts from unit bearings -Open up the CAD (Have a bucket ready, gear oil will drain out) -Remove diff cover (Have a bigger bucket ready, even more gear oil will drain out) -Remove Bearing caps to differential, remembering where each bolt goes and keeping caps in the proper orientation to reinstall them exactly the same way later -Remove intermediate axle shaft by sliding out to passenger end of axle -Install Napa Seal in passenger side of differential - NOTE - the axle tube is not machined for a seal. The Napa seal is the perfect OD for the axle tube and perfect ID for the axle shaft. It will theoretically pound all the way down the axle if you don't stop, so make sure you stop at the point where it rides on the machined portion of the axle shaft. -Swap out driver side seal too since you're in there -Install new axle shafts -Button up the Diff and CAD -Install unit bearings, torque unit bearing axle shaft nuts to 175 ft-lbs -reinstall brakes and wheels -Remove all the old vacuum crap out to the transfer case and engine. [B]The 4X4 Light...[/B] Some people would say "I know when I'm in 4WD, I don't need no stinkin' light." While I don't necessarily disagree with the truth behind that statement, I like things to work as intended. For that reason I chose to rework the 4X4 light circuit to keep it working properly. The factory 4X4 light on 92-95 YJs with the electronic gauges is pretty simple. The light always has fused power with the key is in the ignition. The light is controlled by the ground circuit. The light's ground runs out to the factory 4X4 switch mounted at the CAD. The second wire at the CAD carries the lamp ground out to the grounding point. When the Jeep is put in 4WD, the forks in the transfer case push a button on the 4-port vacuum switch, which connects engine vacuum to the CAD. The vacuum at the CAD motor then slides the CAD fork over, pushing the button on the switch. This connects the two wires together, and the lamp is then grounded and illuminates. When you do the TJ axle swap, you get rid of this setup. The way the TJs and XJs have their light work from the factory is similar, except the wiring goes to the transfer case. The switch I listed is installed where the factory 4-port vacuum switch is on a YJ, and shifting into 4WD pushes the button on that switch, and the lamp is then grounded just like the front axle setup. The only process to making the lamp work is extending the wires to where they reach the transfer case, installing the switch I listed, and crimping on the Weatherpack plug I listed which then plugs into the switch. It is seriously easy as can be. Wrap any wiring in loom to protect it and zip tie it to the other transmission looms to keep it safe. The end result is that when you put the Jeep in 4Hi or 4Lo, so long as the internals of the transfer case move properly, the 4X4 light on the dash will illuminate to reinforce the shift you made. It will shut off when transfer case is in neutral. Overall I am very pleased with this one, I consider it OEM+. It is how the Jeep should have come from the factory, it works, no issues, complaints, etc. So much more reliable than the vacuum mess and it's nice to remove the clump of vacuum tubes and never have to worry about 4WD leaving you stranded. [B]Pictures:[/B] Here you can see the finished front axle, no vacuum tubes, no wiring, and no gigantic flying saucer of a vacuum motor mounted to the axle. Much cleaner. [ATTACH]116948[/ATTACH] Here is the TJ transfer case switch, with my extended wiring ran to it. [ATTACH]116949[/ATTACH] Here is the vacuum tubing at the intake manifold. From the factory, This port tees off to feed the 4WD and the vacuum operated heater entry door. I repurposed this to be for the heater only, now that I have no need for vacuum 4WD. Works flawlessly. [ATTACH]116950[/ATTACH] [/QUOTE]
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My '94 Hunter Green “No Compromises" Build
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