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Good day everyone. I am doing an 8.8 build and install right now. The 8.8 or a Currie 9" are the toughest rear axles available for the TJ. Except for maybe a high pinon Dana 60.
Now then, with all this said, the real question is WHY? Why do you want to go through the expense of such a project. What is it that you really want to do with your Jeep. Set your goals and don’t buy things because ‘it’s good enough for now’. Your throwing your money down the drain. Trust me. Plan your 8.8 axle upgrade accordingly.
WHY: To really answer this question you should ask your self, again, what it is that you really want to do with your Jeep. What percentage of on or off-road is your Jeep going to do. My Jeep, El Diablo, is a 2000 4.0 Wrangler Sport. I run El Diablo about 95 percent of the time off-road. He is trailered to every event. He lives off-road.
Trail Experience: If your going to run mostly off-road, and want to do an 8.8 axle upgrade, some major changes should be done to your Jeep. Get ready to spend some big bucks.
1.) Under Jeep protection (armor) - El Diablo runs with Clayton Off-Road engine and transfer case 1/4" skid plating. (Trust me, the first time you put a hole in your engine oil pan you’ll see why you need this.) Fuel tank skid plate - El Diablo uses a WARN fuel tank skid plate. (That rusted up fuel tank support that comes from the factory is NOT a skid plate.)
2.) Lift (a) - 33" tires will require at least a 2" lift. 35" tires should have a 4" lift. You will also need to install a Slip Yoke Eliminator (SYE) in the transfer case, or snap the output shaft you will. To install a SYE, you will also have to change out the drive shaft. El Diablo uses a Tom Woods Custom Drive shaft. You will also have to change the speedometer gear in the transfer case tail shaft. Your axle assemblies will need to be set up for whatever type of lift you want to use. More on this later. Also, I usually do not recommend anything over a 4" lift because of stability issues.
3.) Rear axle change - Your front Dana 30 axle, believe it or not, is pretty tough. An alloy axle
shaft upgrade for the Dana 30 should work fine. But, the rear Dana 35 axle - unless you have a TJ Rubicon or special order Sport with Dana 44 - when you start running 35" tires, snap an axle you will. Trust me.
▸ Gearing - Running mostly off-road will require you to lower the F&R axle gear ratio. There’s a term called ‘crawling’. Most TJ 4.0 Jeep gear ratios are 3.70. Totally inadequate for serious off-roading. El Diablo runs G2 4.88 gears.
▸ Lockers - Unless you have a TJ Rubicon or special order Sport with Dana 44, your Dana 30/35 axles will have open differentials. Most off roader’s usually use a differential spool, Detroit Locker, some sort of air or electric locker. El Diablo uses ARB Selectable Air Lockers F & R with a heavy duty ARB compressor. Why I don’t like most spools is because they don’t release on sharp corners.
▸ Ford 8.8 upgrade - Why the 8.8 over a Dana 44? Quit actually they are both good axles. But, it gets back to what I originally asked, what it is you really want to do with your Jeep.
Why I choose the 8.8 over a Dana 44 is because the 8.8 is tougher in many ways. First of
all, Ford originally designed this axle for trucks, heavy SUV’s, and performance Mustangs. The
axle shafts themselves in stock form is tougher than an alloy axle shaft for Dana 44 or 35.
Also, the axle housing is thicker and bigger. The axle bearings are bigger. The differential
carrier is heavy duty.
For those U-Tube junkies out there, there is a lot of cheap wrecking yard finds. Take this videos for what they are worth. Trust me, there is no cheap way around any of this.
Once you get your junk yard find, the axle still has to be totally cleaned inside-out. All the original mountings have to be removed and welds ground clean. Then the new mountings have to be welded on before you can begin the axle build.
Now then, I purchased my 8.8 for $20.00. Great deal. Now the axle assembly needs to be upgraded for off-road use and fitment under El Diablo.
Purchased - G2 4.88 gear set, G2 gear set install kit, a replacement yoke for 1310 stock U-Joint, ARB selectable air locker for 8.8 - 31spline, AZTEC Industries TJ 8.8 Swap Kit with Truss, new rotors, brake pads, parking brake shoes, parking brake cables, caliper assemblies, 3x quarts Royal Purple 75w-90 full synthetic gear oil. A few other this & that I haven’t discussed. Around $3,000.00. Yep. If you cut corners in your 8.8 build you will regret it.
Now, why did I want a truss for the 8.8? Simply, the ability to upgrade and added strength to the axle to help keep it from twisting. All welding should be completed to your new 8.8 while its still in bare form.
4.) Lift (b) - Remember I asked earlier what it is you really want to do with your Jeep. Also remember I told you to get ready to spend some big bucks.
Short arm lifts are the most economically way to go. They are good up to a 4" lift. Articulation is good for most aftermarket brands. Make sure to shop wisely.
However, long arm kits, in my opinion, are superior in many ways. I mentioned articulation. They articulate better and at a faster rate. They absorb the pounding better. Also they hold your axle assemblies in place better. There is also a better selection of high grade shocks available. Remember, plan your 8.8 axle upgrade accordingly.
El Diablo will have a GenRight Off Road 4 Link Rear Kit, Double Triangulated with Johnny Joint Links mounted on his 8.8. Why I chose this, because the triangulation will hold the 8.8 axle firmly in place in any direction at any speed. And I can mount Fox or King brand shocks.
There really is way too much information to cover, as you can tell. I hope some of this helps.
Milt