SlowLeak

Hi everyone, I am new to the forum as well as the XJ world. I recently bought a 98 Cherokee Limited. It currently has a 6.5 skyjacker short arm lift w/ sway bar disc, 35" Cooper STT Pro tires, Chrysler 8.25 rear, Dana 30 front.

I'm ready to start building it and have set aside a budget of about $6,500 for the build. I figured I would start with the driveline as that is typically the weakest part. I would like to keep the Chrysler 8.25 to save some money, but I'm not sure the gear ratio in it (haven't pulled the cover yet), the build sheet says 3:55 (I'd like to go with 4:88).

So here I am (sorry for the redundancy). I will be driving it on the road quite a bit, but I also have a DD. Should I lock or weld the rear (if locker is the way to go then which one is best for my budget)? Should I lock or leave the front open? Reliability is key for me as I will be wheeling with my 3 small children (not anything too crazy, but some tough obstacles). Also I'm purchasing a front bumper, rear bumper, rock sliders, winch, and quarter panel guards. I spoke with a local differential/axle shop that said he could do an 8.8 swap in the rear, Yukon 4:88 gears, and lock the front for around $3,000. Which I thought was fairly cheap, but still eats about half of my budget. So I don't know which direction is best here. I'm a automotive technician so most of the work will be performed by me (unless I let the local diff/axle shop do it for the warranty he offers). So please tell me the do's and dont's from being much more experienced in the jeep world than I am.

PS: I'm not new to the wheeling world however, I have had 2 samurais, an 83 hilux, and currently also own a 4 seat RZR. Just new to the jeep world. Thought that might be important information when asking for advice. Thanks in advance.

TRCM

1) Don't weld the rear if it is being daily driven

2) I prefer a locked rear and an open front, but there are those on here who don't. It's kind of a personal choice as to what you are use to and/or comfortable with. If you lock the rear, and put a selectable in the front ($$ I know), you will have excellent traction when in 2wd, and crazy traction when you lock in the front in 4wd (I have yet to come across a situation where I needed the front locked so mine isn't, but I don't wheel any harder than you do it seems)

3) How is he gonna lock the front for 3k ?? a lunchbox locker is 300 bucks.....but the price isn't too bad as he is swapping in an axle, putting in new gears & setting them up in 2 axles, and putting a locker in the front. Hopefully, the 8.8 swap also includes disc brakes.


I would also consider control arm drop brackets or long arms at that height. That short arm has to be a rough riding SOB....mine rode like a buck board @ only 4.5"




.

Stroked98Xj

If you're new to wheeling Jeeps, I'd actually leave both axles open until you get some experience under your belt and feel where the need is, in regards to locking an axle. You might find that your personal wheeling style suggests a locked front over a locked rear, or vice versa. You don't really know until you've gotten stuck and frustrated a couple times.

3.55's, 4.0L and 35's must suck. Wheel in 4LO as much as possible to save on the transmission and install a tranny cooler ASAP!

4.88's are a good match for 35's if you plan to tow anything heavier than a duck boat, but 4.56's would be better suited to a daily driver that sees a lot of road miles. Neither are ever going to allow you to see 20mpg again, and if you have a DD that's meant for fuel efficiency, then I'd run whichever set is cheaper and just be happy with it. The strength differences between 4.88's and 4.56's are negligible when we're talking about a Dana 30.

If it were my Jeep, I'd buy frame stiffeners to save the unibody "frame", and I like your initial idea of front and rear bumpers, and sliders. See where your 6.5" lift springs sit after you add some weight, then consider cutting the coils or lowering the Jeep down to a full 4-4.5" lift height. You don't need all that lift for 35's and for the times when you're on the road, you will appreciate the improved cornering+handling and softer ride. Driving for 4+ hours at night and suddenly seeing a deer in your lane is what I have in mind for the "oh ****" necessity of good handling of a big Jeep. Been there, pretty sure those boxers are still soiled. Sway bars were disconnected too

The 8.8 swap is nice, but does come with its own bull-$hit to deal with. Wait to swap that in when the C8.25 becomes inadequate, or you break it. For now it's strong enough and has good enough brakes to handle 35's and the 4.0L while sporting an open diff. Like I said, wheel first, spend money later.

If you're new to Jeeps, especially the 4.0L Cherokee, know they have overheating problems. Use your automotive technician training to go through all the cooling system components. Replace, upgrade or freshen up as necessary. The cooling system is the #1 thing I deal with when off-road in XJ's.

And again, get a transmission cooler. My favorite is a Super Duty cooler from a junk yard. All aluminum, roughly 20" wide, 7-9" tall and fits nicely behind the grille. Usually comes with a thermostatic valve built in that opens after the trans fluid gets warm enough, which means you can bypass the trans lines into the radiator and just use the trans cooler for the tranny. This will save the radiator from having to cool your trans cooler as well, which leads me back to #1 problem in the paragraph above.

Good luck! And welcome to being broke for the rest of your life.

SFNM94XJ

Ditto: Don't drive a welded diff on the street.
Ditto: For 6" lift switch over to long arms. Makes a world of difference. Also I ditched my poly bushings & went back to rubber. Much better on the street.
Ditto: 4.88 gears with 35" tires. Good combination of low end grunt and reasonable highway rpms. Just did a five hour drive at 65 and got 19.5mpg; 5 speed.

Baddad

#1 - FRAME STIFFENERS! World of difference! These look good;
https://www.hooliganoffroad.com/collections/xj/products/xj-full-stiffener-system
I run the center part of these;
https://www.ironrockoffroad.com/product/xj-unibody-frame-stiffeners-full-set.html
i like both of these designs because they wrap around the frame area more.
If your wheeling like you describe, at least run the center/mid section stiffeners, they are the ones that'll do the most.
#2 - Long arms or lower lift height. I run 3.5" with short arms in the front, loving it! My wheeling buddy went 5.5" with short arm, hated it! Then he tried lower control arm drop brackets which made things better but he got a lot of creaking noises. Finally he went IRO long arms and loves it! Anything over 4-4.5" lift, long arms are the way to go! Oh, and Bilstein 5125 shocks, best bang for your buck imo.
#3 - 4.88 gears with a locker in the rear. Personally I'd do the 8.8 from an Explorer with discs. Most bang for your buck! I run 35's with this setup and it works awesome. I would avoid locking the front until/unless you run a steering assist system. Hard to steer those 35's locked up with stock or aftermarket steering without it on the trail in any sort of bind. 4 Xj's in our group, all running different steering setups, all running front lockers and 35's, we all had this steering issue!
I almost forgot! If you have the stock steering setup, ditch that factory tie rod and upgrade to the V8 ZJ one! It's a bolt in mod and a HUGE increase in strength! Cheap to do to 🙂
Thats my .02 😋

SlowLeak

Ok sorry for the long delay but I wanted to give an update and say thanks for all the great advice! Since my last post I installed 4.56 gears, a lock right locker in the front, and I went against the grain a little bit and welded the rear. I kept the C8.25 rear and left the axles alone for now. I bought a rustys long arm kit and ruff stuff specialties HD tie Rod kit. Also I went with smittybuilt on the bumpers and winch. I got the 10k lb waterproof with the wireless remote.

As as far as the overall mechanical condition, it's in pretty good shape. It has a single cylinder miss on cold start up, with an o2 sensor DTC. So I'm assuming the o2 sensor is more than likely the culprit if it's not heating up quickly enough, or at all. It already has a factory transmission cooler on it, I thought maybe because it's a limited? I'm not sure though. The previous owner installed an electric fan with a toggle switch that seems to do a very good job so far. It does, however, have a growling noise only when letting off the accelerator at highway speeds (40mph+). It almost sounds vibratory but in turn makes a metallic rattle noise as well (which I think might be a heat shield, but I don't know). It sounds like it's primarily coming from the rear, but I replaced everything in the rear axle housing but the carrier, and it made no difference. So I'm kind of stumped. Thanks again for the advice thus far, and thanks in advance for advice from here.

Baddad

Sounds like your off and running! Don't forget frame stiffeners. They really are worth it, especially with the long arm setups.

SlowLeak

I'll definitely need to get me some of those. I don't want my doors to stop closing on me. haha. I need to get some of these bugs work out first, like the misfire and groaning noise. I think the groaning noise is possibly driveline vibration. It changes with speed and doesn't really occur until about 40-45 mph, and only when letting off the gas. It has a 6.5" lift but still has the slip yoke. Could that possibly be the issue? Its a very fast vibration that seems to be resonating and causing a small heat shield rattle.

Baddad

Definitely time to do some sort of sye and double carden driveshaft setup. Search this forum there is tons of info on it about this.

SFNM94XJ

Ditto on Baddad's suggestion. That may very well be the source of your off-throttle driveline vibrations. Also: check the big nut holding the driveshaft yoke on the front side of the diff. I had the same issue and it was simply that nut was loose. Don't remember the spec, but it is a lot of torque on it.

Bugout4x4

3/4 drive air wrench type torque...

Stroked98Xj

Sounds like you have a worn output bearing and/or race in the transfer case. Its accelerated wear was caused by the huge lift with no attention to the driveshaft. I'd address the entire problem by rebuilding your t-case, and installing a slip yoke eliminator. Check the front drive shaft as well for correct length. I'm guessing you are near the end of the travel on your front shaft already, and long arms will certainly emphasize this.