1995 Jeep Wrangler Lift, Tires, Axles, and Interior Upgrades
A look back at how Hazel took a plain Jane YJ from zero to hero.
Here's another project recap of a vehicle I built back before social media existed and before our websites really stored and aggregated photo captions and images correctly. If you've got old print copies of Jp magazine from the 2004-2005ish time frame, you probably have some of these original stories, but as I've done with several of my more popular vehicle builds, I thought I'd take an opportunity to dig through the old hard drive and collect some key highlight images and expound on them in the limitless confines of the internet to show the good, the bad, and the ugly of a 1995 Jeep YJ Wrangler project build I affectionately called Project GJ.
After finishing my flattie build in mid 2003 I was towing with an '89 big-block Ford F-250 4x4 and commuting from San Diego to Los Angeles in my '85 Toyota 4Runner. While the 4Runner was a great vehicle, it wasn't a Jeep and I was working at a Jeep-only publication. I decided to let my 4Runner go and used the proceeds to purchase a Wrangler that I could use for some tech fodder in the magazine and drive on my 126-mile commute each way to and from the office. I found a 110,000-mile '95 YJ for sale in Costa Mesa, California, with the MPI 2.5L, AX5 transmission, and not much else to offer. Since it was sort of on my way to work, I arranged to meet the seller in the morning figuring I could buy the Jeep and then continue on up to the office, not having to miss work or impact my schedule that badly.
The YJ was nothing to brag about despite its $3,200 price tag, but the seller got it to pass smog and I thought we'd just trade cash for title and registration and I'd be on my merry way. However, unbeknownst to me, the seller didn't hold the title—a nice little fact he neglected to tell me about before I drove 1.5 hours with my trailer in tow to buy it. What followed was an all-afternoon suckfest of waiting for him at the DMV while he stood in a huge line to get the title in his name, then transferred to me.
It put me back several hours, but I finally got the Jeep loaded on my trailer and towed it up to work. I kept looking down out of my window at it in the parking lot, dying to go give it a closer inspection and take it for a test drive, but that would have to wait until I got home the next morning. I got home from work around 1:00 a.m. and hit the hay for a couple hours before tearing off to the driveway to inspect my new pile.
In the light of day, I was able to drop the YJ off my trailer and give it a closer look. The top was hammered, with windows so yellowed by the sun you could hardly see out of them. And the front zip-up windows had both been slashed with a knife, probably by some thief sometime in the past. I put "order new top" on my to-do list and continued my inspection.
Although the Jeep passed smog with flying colors, it ran rough, had an off-idle stumble, and the idle was super choppy. I gave it a tune-,up with new plugs, wires, air filter, cap, and rotor, and I cleaned a ton of gunk and oil out of the throttle body. After that it fired right up and idled as smooth as a sewing machine. The off-idle stumble was gone, and it was actually a really nice driver.
The interior was nothing to write home about, so the first thing I did was a complete interior and top upgrade. I ordered a Poison Spyder weld-yourself front cage kit composed of floor plates, dash stanchions, and bars to complete the front cage.
Although the driver-side stanchion impeded the e-brake release lever (I just turned the handle from horizontal to vertical, and it worked fine), the Poison Spyder stations hugged the dash nicely and allowed the doors to close with no problems. While I was at it, I added a Tuffy Security glovebox insert to the dash.
I rounded out the interior update with new Bestop front and rear seats, a Tuffy Security center console, a Bestop Sound Bar, and a new Grant steering wheel.
I was building Jp's '99 XJ Cherokee at the same time as this Wrangler and had the factory Jeep Grizzly wheels and 225/75R15 Mickey Thompson MTX tires sitting around, so I tossed the XJ wheels and tires on the YJ, which fit perfectly with the stock suspension. The look and on- and off-road performance were night and day from the dry-rotted Lemans bargain-basement tires the Wrangler was wearing when I bought it. In this configuration the Jeep got 20-23 mpg at freeway speeds during my commute to and from the office and was super comfy and reliable.
After the new interior and top were in place I turned my attention to some lightweight armor and bumpers. The aluminum Poison Spyder rocker guards (now discontinued) were one of the first aluminum armor solutions on the market, and for a project like this, which wasn't intended to be smashed across rocks every weekend, they made a smart lightweight solution to steel armor.
The all-aluminum Truckmaster Design bumpers were strong yet half the weight of steel. I really liked the look, fit, and heavy construction they offered, but unfortunately these bumpers are no longer produced. For simple trails like those in the deserts around Los Angeles and San Diego the aluminum armor was more than fine and would've handled harder trails like the Rubicon with no problems.
The 0.25-inch-thick PSC aluminum rockers were a great-looking feature that had more than enough strength to support the weight of the 3,300-pound YJ. The biggest disadvantage to aluminum armor is it's much softer compared with steel. Where steel will slide over many rock features without much issue, aluminum tends to dig in and stick to rocks.
In all honesty, I was really happy with the little Jeep with the drivetrain completely stock and the small tire size. It was sprightly around town, got great highway mileage, and with the swaybars and track bars removed, did fairly well off-road. However, one day while I was driving around town, the cat brick dislodged and choked the engine badly. I took the opportunity to make some power upgrades with before-and-after dyno numbers. For the exhaust, I used a very nice Banks header, a Magnaflow catalytic converter, and a Banks after cat exhaust.
To support the free-breathing exhaust, I nabbed the factory 58mm 4.0L throttle body that I had taken off my '99 Cherokee and transferred all the 2.5L sensors over.
The larger bore of the 4.0L throttle body holds more potential for airflow for things like superchargers or turbos, but in all honesty the otherwise stock 2.5L really didn't need it.
I capped off the underhood upgrades with an AEM intake, Flex-a-lite electric fan, and a custom-tuned Unichip. In completely stock form, the Jeep made 100 hp and 121 lb-ft at the rear tires. After all the modifications it made 114 hp and 128 lb-ft at the rear tires. However, although the Jeep technically made more horsepower and torque, both came only at higher rpms. And what's worse, the low-end numbers under 3,500 rpm were way down compared with the Before numbers, making drivability worse. And as insult to injury, the 2.5-inch exhaust was so loud it set off car alarms. On this particular application it was a much happier little engine before I messed with it and I found myself frequently wishing I had just replaced the bad catalytic converter with a one Magnaflow and called it a day.
With the pin pulled on the engine mod hand grenade I decided to dive into the suspension and axles, selecting a 3.5-inch Superlift suspension system that was very complete. Superlift had full front and rear replacement springs, all the hardware and brackets necessary for the lift, shocks, a slip yoke eliminator, and Superlift's TrueSpeed electronic controller that allowed you to correct the electric speedo after you made tire diameter or axle gearing changes.
I got the Superlift suspension installed in an easy afternoon with no problems at all. Back then you could go to any off-road shop and find a decent supply of take-off YJ springs, but nowadays they're getting a bit harder to find. I stashed the springs in my shed as spares for my flattie. I wound up using one of them a few years later when I snapped a main leaf on my '53 Willys. The other three are still out in my shed patiently waiting.
Even though the Superlift springs came with steel degree shims installed to compensate for the lift, at 3.5 inches the resultant driveshaft angles aren't workable without some sort of correction, as this shot of the stock rear driveshaft with the Superlift springs indicates. The Superlift suspension system included pucks and longer bolts to drop the transmission/transfer case crossmember, but I chose to forgo this route and crack open the NP231 to install Superlift's optional slip yoke eliminator.
I had a front 1310 CV driveshaft kicking around from a past project that was still in good shape, so I brought it down to Oceanside Driveline in Oceanside, California, to be shortened to fit. The new shaft dropped in perfectly, and the degree shims on the Superlift springs, coupled with slightly longer shackles, pitched the pinion yoke of the stock Dana 35 rear axle up enough to work nicely without any buzzing under load, although I did get a very slight buzz upon deceleration.
The lift cleared enough room to mount a set of 33x12.50R15 Firestone M/T tires on 15x8 forged Weld Racing wheels. The front had no issues at all, but the rear tires would kiss the back of the flare and wheel tub on hard bumps. I trimmed a bit of the flare plastic on the back and peened back the tub lip with a hammer, and all was good. Well, almost everything. The big tires made fifth gear useless with the 4.10 factory gears, but it looked cool and rode nice!
The last piece of the puzzle was gearing and axles. With 33s and a 2.5L I really needed 4.88s at minimum or ideally 5.13s or 5.38s. But I went the dumb way and decided to swap the Chrysler 8.25 I had left over after installing a 9-inch in the rear of my '99 XJ. The tallest gear for the XJ rear I could get at the time was 4.56, so I ordered the gears from Yukon for the high-pinion Dana 30 front and XJ 8.25-inch rear.
I ordered an Auburn limited slip for the XJ's 8.25-inch rear because at the time it was one of the only performance-oriented limited slip options available for that axle. However, I found the Auburn came with some complications on the install. I began by pulling the stock 8.25-inch carrier bearings so I could hog them out a bit to build some makeshift setup bearings.
The first hiccup came after installing the big 4.56 ring gear on the Auburn limited-slip. It turns out you need to either nip a bit off one of the ring gear teeth or clearance the cross-shaft. I left the ring gear teeth alone, choosing to grind the cross-shaft for clearance.
Another issue was the Auburn carrier didn't quite fit inside the 8.25 XJ axlehousing. Using a grinder, I had to nip a bit of the bearing cap support out. I went slowly and carefully at small increments test-fitting the carrier after every pass. I left a few thousands' clearance to allow for expansion as the unit got hot under heavy use but left as much material as I could. Up front in the stock Dana 30 high-pinion housing, I used an Eaton Truetrac, which took the 4.56s much, much easier.
With the 8.25-inch axle regeared to 4.56, I used my Miller plasma cutter with a gouging tip to buzz off the stock spring perches so I could swap them from the XJ spring-over to YJ spring-under configuration. Cutting carefully, I was able to reuse the stock perches to save some coin.
The YJ Dana 35 (top) is the same width and has the same pinion offset as the XJ axle (bottom). The vents are in a similar spot, and the hard brake lines even transferred over. The XJ axle doesn't have a track bar bracket, but I don't use a rear track bar bracket on YJ applications anyway, so no big deal. The only thing that wasn't the same was the YJ E-brake cables, but I was able to hook the XJ cables up to the YJ brake bracket on the frame and retain functioning E-brakes.
I slung the XJ axle under the YJ and loosely positioned the spring perches on the axletubes. When I was happy with my side-to-side measurements ensuring the axle was well and truly centered, I used the YJ spring plates and U-bolts to cinch the axle to the springs with the pinion perpendicular to the floor, but I didn't weld anything yet.
The spring U-bolts held the axle tight enough to the springs that it didn't walk or droop. With jackstands supporting the weight of the vehicle, I installed the rear driveshaft back in the vehicle and used a floor jack to gently rotate the pinion up so it was 2 degrees under the driveshaft angle. That allowed some slight upward rotation of the pinion under load and alleviated the driveline buzz upon deceleration. With the pinion where I wanted it, I tack-welded the perches in place, pulled it all back apart, and then finish-welded the perches.
The final piece of the puzzle was working out the rear shock mounts on the axle. I could've used a couple simple tabs, but after a few minutes of searching my spare tab bin, I just decided since the plasma cutter was out to zap off the stock Wrangler shock mounts from the Dana 30 and install them on the Chrysler axle. The 8.25-inch axletubes are a slightly larger diameter than the Dana 35, but an angle grinder quickly opens up the radius for a perfect fit.
I settled on 4.56s laboring under the assumption that someday I'd wind up pulling the trigger on a Dodge 5.2L Magnum and AX15 drivetrain swap. That never happened, and even though I did notice an ever-so-slight improvement going from 4.10 to 4.56 gears, it really wasn't worth the hassle and effort of the gear swap. If I had it to do over again, I would've gone to the junkyard and found a Ford 8.8 and swapped that in with a set of 5.13 gears. That would've made driving this Jeep on the road a much nicer experience.
The Dyno Shop
Poison Spyder Customs
Yukon Gear & Axle