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OEM+ (or "Super Stock") XJ build questions

M

maalox

NAXJA Forum User
Location
Va
Now that I've got all of the maintenance and repair items taken care of on my XJ, I'm planning some upgrades. I have historically built all of my vehicles as I felt they should have come from the factory, and I want to do the same with my XJ. This means subtle, functional upgrades that work without a bunch of hassle. I prefer upgrading using factory parts from other vehicles if at all possible, to save on complexity and cost, and maintain availability of replacement wear parts. I've got my plans for armor and bumpers covered, lighting stuff is just about done already, the only thing that remains is suspension and drivetrain. That said, I am new to 4WD, and solid axles, so there is a bit of a learning curve, please bear with me.

Here's what I'm working with:

89 XJ Limited 4.0L AW4. Non-disco HP D30 up front, NP242, D35 rear. This truck originally had ABS, which I ditched and replaced with '96 XJ non-ABS booster, lines, and hoses. It's currently on a 2" BB(front spacers and rear shackles) with ZJ Canyon wheels and 30x9.5" BFG ATs. It's also got polyurethane bushings in the control arms and leaf eyes.

My use of the truck does not currently include a ton of wheeling. It's clean and rust-free, and I have no intention of bashing it off of rocks and trees anytime soon. So the plan is to build a truck that is capable both on- and off-road, and in inclement weather(snow). It needs to be able to handle medium-duty off-roading(fishing/camping/hunting/skiing trips) and be seamless enough on-road that my old lady can drive it without an instruction manual or fear of breaking something due to improper use.

So, here are my thoughts as to how I want to build this thing, please suggest any changes or correct any errors I may have made:

Transfer case: The NP242 stays, unless there is a very convincing reason to get rid of it. The Full Time feature is one of the reasons I bought a Limited in the first place, and has proven quite useful for winter conditions in my area.

Front Axle:
The HP D30 Non-disco seems to be the way to go, especially since it's originally an ABS-equipped axle, and as such should have the larger 297 joints(I haven't confirmed that). Aside from a full teardown and rebuild with new berings/seals/etc, these are the upgrades I intend to do:
*ZJ V8 tie rod
*Detroit Tru-Trac planetary LSD
*WJ Outers?? (I've read a little about this, I'd like a little further input on the necessity and complexity of this modification)

I would like to upgrade the brakes if at all possible, but I do not want to make any wheel changes, so any upgrade will need to fit under stock-sized wheels.

Rear Axle:
The D35 has to go. I thought about an XJ D44, but they are nearly impossible to find, and costly when they can be found. It seems that adding disc brakes is more complex on a D44 than a Chrysler 8.25 as well, so I've decided to go with less expensive, more readily available 29-spline 8.25. Planned upgrades:
*Detroit Tru-trac
*ZJ Rear disc brakes

Any thoughts on gearing? I have considered a change to 3.73 or 4.10 R&P, but I would like some thoughts on which would be better for all-purpose use. I don't intend to go bigger than 31's, and I don't really plan to do any towing. Fuel economy is a little bit of a concern, as it's already a gas hog.

Driveshafts:
I would love to get rid of the double-cardan joint in the front driveshaft if it's economically viable and not a major hassle. For the rear - it looks like I will need the driveshaft that matches the 8.25, is there anything special I need to do to mate it with the NP242? Is a SYE necessary?

Suspension:
*OME 2" springs, front and rear. I intend to keep the spacers and shackles I'm currently using, to get to about 3.5" of total lift.
*OME or Bilstein shocks
*WJ LCAs (for tire clearance)

I'd like some feedback from you guys, as the wealth of knowledge here seems pretty unlimited. I've done a bunch of reading to come up with this setup, but having never actually done it, I'm sure I'm missing something or have something wrong somewhere. Thanks, everyone!
:cheers:
 
Tru-tracks and a -242. Sweet setup. You're going to love that.

For 31" tires, go with the 4.10 gears.

The WJ outers are for the brakes. It's a substantial upgrade over the stock single piston setup.

Why switch the front driveshaft? You would have to reset the front pinion angle to do it right. 'Nothing wrong with the double-cardan joint.
The fixed output yoke isn't really necessary until you go with huge travel, or start to run into vibration problems when the stock shafts joints get out of phase. At 3" +/- lift, it's a tossup if you'll have vibes or not. No way to tell until you drive it.
 
Last edited:
This is exactly the build I'm starting. Except I plan on keeping all the bushings rubber. Keep us posted. I'd like to see how everything goes.
 
maalox said:
Rear Axle:
The D35 has to go. I thought about an XJ D44, but they are nearly impossible to find, and costly when they can be found. It seems that adding disc brakes is more complex on a D44 than a Chrysler 8.25 as well, so I've decided to go with less expensive, more readily available 29-spline 8.25. Planned upgrades:
*Detroit Tru-trac
*ZJ Rear disc brakes
Click to expand...
You can also use rear discs off a Liberty with them iirc. The Liberty also uses an 8.25 rear (coil sprung) so you can swap the backing plates and whatnot right over.

maalox said:
Driveshafts:
I would love to get rid of the double-cardan joint in the front driveshaft if it's economically viable and not a major hassle. For the rear - it looks like I will need the driveshaft that matches the 8.25, is there anything special I need to do to mate it with the NP242? Is a SYE necessary?
Click to expand...
X2 on what tbburg said, the double cardan at the front is really not an issue, works fine and doesn't really wear out fast (mine is still going strong at 138k.) In fact, a lot of guys on here solve their rear vibration problems after lifting by using another front shaft as a rear shaft for a hack-n-tap SYE. No way to really tell if you'll need an SYE till you lift it and drive it.

maalox said:
Suspension:
*OME 2" springs, front and rear. I intend to keep the spacers and shackles I'm currently using, to get to about 3.5" of total lift.
*OME or Bilstein shocks
*WJ LCAs (for tire clearance)
Click to expand...
Sounds good. Don't get the springs I did (OME 2" HD CS035RAs and OME934s) or you'll end up with 3.5" from just the springs. Not that I'm complaining, of course. WJ LCAs will help out rather nicely and are cheap at your local yard if you feel like crawling under a junker and screwing around with a breaker bar and 21mm socket for a while. I'd have a set but I was too lazy to haul the hydro jack into the yard yesterday and couldn't get a good enough angle to just sawzall the brackets, though I tried.
 
tbburg said:
Tru-tracks and a -242. Sweet setup. You're going to love that.

For 31" tires, go with the 4.10 gears.
Click to expand...

Agreed on both. This is very similar to the setup I'm running in my 2000 Limited, and I'm very happy with it. Going from 3.55 gears to 4.10s with 31" tyres was like night and day both in terms of performance and economy.

The only thing I'll add to this is that if you're looking at 2" OME springs, go with the 3" heavy-duty springs instead and put some 4-degree axle shims in the rear. While I realise you're not planning on serious trail use for this XJ, It'll give you more useful clearance for 31" tyres when you do need it. The one caveat I'll bring up about this is that if you do go to 3" you may want to go to an adjustable trackbar after lifting it.

Stock control arms are OK up to 3" in most cases. WJ units are beefier, but for the sort of use you're outlining may not be entirely necessary. I ran my stock ones without trouble on some less-than-forgiving trails until I went to 4.5", at which point adjustables were necessary.
 
Why does the d35 have to go ? a 89 d35 is a non c-clip. With 31" I think you'll be fine.. also from what you plan on doing with it, should be fine. Do you have any plans on locking the rear ? You could upgrade it even - and make it even more stout and handle 31" without worrying about breaking it.

Another thought would be.. you can get a pair of axles with 4.10 gears stock, and save on gear installs. But this would be a d30/d35 combo(as d44's are hard enough for you to come by).
 
Tough call, but if you're going to be doing a re-gear/disc upgrade/differential swap on a 8.25(could obviously save money and find a 4.10 8.25, but,...)You might want to consider a ford explorer 8.8 swap instead. I know it's not factory parts, but, a little searching(not much) can turn up an explorer rear axle with 4.10 gears, disc brakes, and a limited slip(clutch type) that's a pretty easy swap. You could finish the rest of the build, and then swap in a rear tru-trac at your leisure. It would save the cost of rear gears and rear discs.
 
dan89XJ said:
Why does the d35 have to go ? a 89 d35 is a non c-clip. With 31" I think you'll be fine.. also from what you plan on doing with it, should be fine. Do you have any plans on locking the rear ? You could upgrade it even - and make it even more stout and handle 31" without worrying about breaking it.

Another thought would be.. you can get a pair of axles with 4.10 gears stock, and save on gear installs. But this would be a d30/d35 combo(as d44's are hard enough for you to come by).
Click to expand...
Or he can just spend a hundred bucks on a pick-n-pull 29 spline 8.25 and not worry about it at all ;) There is no reason to polish a turd when it will cost more to polish it than it will to put an axle in that will be strong enough in stock condition.
 
tbburg said:
Tru-tracks and a -242. Sweet setup. You're going to love that.
Click to expand...

Glad to hear that. I really want to avoid the added complexity of lockers for the sake of my sanity while my old lady is using the truck. She has a hard enough time with the part-time vs full-time thing and when to use what. :roll:

For 31" tires, go with the 4.10 gears.
Click to expand...
Are there any modifications I can/need to do to help correct speedometer error?

The WJ outers are for the brakes. It's a substantial upgrade over the stock single piston setup.
Click to expand...
I did a little more reading on the WJ outers, and I'm concerned that this may cause me to have to go with aftermarket 15" or even 16" wheels to clear the brakes. Any clarification on this? I'd like to retain the 15" OEM wheels I've got.

kastein said:
X2 on what tbburg said, the double cardan at the front is really not an issue, works fine and doesn't really wear out fast (mine is still going strong at 138k.) In fact, a lot of guys on here solve their rear vibration problems after lifting by using another front shaft as a rear shaft for a hack-n-tap SYE. No way to really tell if you'll need an SYE till you lift it and drive it.
Click to expand...

OK, so the front shaft stays. Maybe I'll just give it a rebuild while it's all apart. Should I be looking into a T-case drop for the rear?


Sounds good. Don't get the springs I did (OME 2" HD CS035RAs and OME934s) or you'll end up with 3.5" from just the springs. Not that I'm complaining, of course.
Click to expand...
Wouldn't it be better to get all of the lift out of the springs, as opposed to springs and spacers/shackles? If that's the case, I'll just go that route. I've heard about using V8 ZJ OME coils up front for a more heavy-duty application. I do plan on running an ARB Bull bar and a winch, which I know will add significant weight to the front of the truck.

WJ LCAs will help out rather nicely and are cheap at your local yard if you feel like crawling under a junker and screwing around with a breaker bar and 21mm socket for a while. I'd have a set but I was too lazy to haul the hydro jack into the yard yesterday and couldn't get a good enough angle to just sawzall the brackets, though I tried.
Click to expand...
Let's just say I have an inside guy at a Chrysler dealership, so I get all of my OEM stuff VERY cheaply. And I have access to wholesale junkyard suppliers. This is one of my motivating factors for upgrading with OEM parts.

tbburg said:
Tough call, but if you're going to be doing a re-gear/disc upgrade/differential swap on a 8.25(could obviously save money and find a 4.10 8.25, but,...)You might want to consider a ford explorer 8.8 swap instead. I know it's not factory parts, but, a little searching(not much) can turn up an explorer rear axle with 4.10 gears, disc brakes, and a limited slip(clutch type) that's a pretty easy swap. You could finish the rest of the build, and then swap in a rear tru-trac at your leisure. It would save the cost of rear gears and rear discs.
Click to expand...

I read up on the Ford 8.8, and I decided I'd rather stay with the rear axle originally designed for the truck, so I can keep my modifications internal/bolt-on. If I can find one with 4.10 gears in it already, I'll do that. I want to build at least the rear out of the truck, then swap it all in as an assembly. If I can find another inexpensive ABS-equipped D30 front, I will grab that, too, again in the interest of building it out of the truck and then swapping it in. I prefer that route to avoid downtime, and it helps me take my time and not rush through it just to get the truck back on the road. IIRC, it's the 4-cylinder automatic trucks that came with 4.10s??
 
Perhaps I am looking at this a bit more from the economics side of things.

We have a rust free, straight XJ with a BB and 30's. He doesn't wheel except for an occasional forest road. He wants a dependable rig, and I assume reasonable gas milage.

My recomendation is to stop now. The rig is dependable, and reasonably stock. It will get you everywhere you go (to and from work, the Mall, the fishing hole...) Your Old Lady can drive it and be absolutely safe as can be.

Money spent: $0

Yes, I read the OEM equipment list, and it does not scare me the slightest. I've wheeled may rigs on 235s and a few inches of list, much more ruggedly than just going out to the fishing hole, or to a favorite huntng spot up a Forest Road on 30's. And I have done so with a standard D30 and a D35.

If you want to spend the money on a 8.25, see it you can get one out of a 97 and newer with a tracklock installed ( look for a FS spare in the rack), and get the DS at the same time.

Ron
 
Ron's got a point, Dad ran both of his Renix trucks with 235's, RS5000's on the front, and Airshocks on the rear on an otherwise stock truck when he worked for a local railroad as his work truck (he was a track maintanence manager.) He ran both trucks to over 200k, had 500+ pounds or railroad stuff in the back (hence the airshocks!), ran them on our wonderful Chicago area roads, along on and over the right of ways (which aren't always as rough as the roads are!), as well as an occasional family hauler! Right now my '98 is set up in much the same way, it mostly hauls my r/c stuff around now, but has been used as a family hauler and occasion delivery truck when the second hobby shop I worked at was still open (airshocks came in handy there too!)
 
maalox said:
I really want to avoid the added complexity of lockers for the sake of my sanity while my old lady is using the truck. She has a hard enough time with the part-time vs full-time thing and when to use what. :roll:
Click to expand...
There might be a problem here. Are you talking just driving around, or off-roading? To get the full benefit of the truetracs, you have to learn to drive with both hands and both feet - as in, using left foot braking and/or engaging the e-brake with your right hand, while steering with the left hand and applying gas with the right foot to "lock up" the front. rear. or both diffs.(It's a technique that works with any limit slip dif, and to a small extent with an open dif, but gives amazing results with a truetrac)
maalox said:
Are there any modifications I can/need to do to help correct speedometer error?
Click to expand...
You might not have to do any modification at all. When I had stock tires(225-70x15) my speedo read a little slow( about 2mph@60) When I put 30x9.50-15 on it, the speedo was dead on with no change.(compared to a GPS) I swapped in 3.73 gears, which should have brought everything back to stock ratios, the speedo was slow again.
So, if your speedo is as (in)accurate as mine is, if you drop from 3.55 gears to 4.10s then up tire size from 225/235s to a 31", you might be dead on.(math says about 3.90s would be similar ratios, 4.10 are the next closest available)
Worst case, you slip in a new speedo gear, a 10 minute job.
maalox said:
I did a little more reading on the WJ outers, and I'm concerned that this may cause me to have to go with aftermarket 15" or even 16" wheels to clear the brakes. Any clarification on this? I'd like to retain the 15" OEM wheels I've got.
Click to expand...
Not sure about this. 'Never researched it much. A lot of the early grands(ZJ) came with 15" rims. I Know a 16" will clear, that's the factory size. But again, I've never researched it.
maalox said:
Wouldn't it be better to get all of the lift out of the springs, as opposed to springs and spacers/shackles? If that's the case, I'll just go that route. I've heard about using V8 ZJ OME coils up front for a more heavy-duty application. I do plan on running an ARB Bull bar and a winch, which I know will add significant weight to the front of the truck.
Click to expand...
The spring/shackle combo are part of a same system. When you add a lift spring, it's longer the the stock spring. Depending on the difference, you may HAVE to get longer shackles to allow the spring to work properly. Getting a 2" spring and an inch longer shackle is a pretty good combo. Also, the longer shackle will move less for the same amount of flex, saving wear on the bushings.
Up front, the spacer on spring is a little less durable then a longer spring, when you flex it out a lot.(shorter spring compresses more) On-road/trails, not really noticeable.
maalox said:
I read up on the Ford 8.8, and I decided I'd rather stay with the rear axle originally designed for the truck, so I can keep my modifications internal/bolt-on.
Click to expand...
Nothing wrong with the 8.25. You'll spend a little more money putting it together, but all the parts are available.
 
Zuki-Ron said:
Perhaps I am looking at this a bit more from the economics side of things.

We have a rust free, straight XJ with a BB and 30's. He doesn't wheel except for an occasional forest road. He wants a dependable rig, and I assume reasonable gas milage.

My recomendation is to stop now. The rig is dependable, and reasonably stock. It will get you everywhere you go (to and from work, the Mall, the fishing hole...) Your Old Lady can drive it and be absolutely safe as can be.

Money spent: $0

Yes, I read the OEM equipment list, and it does not scare me the slightest. I've wheeled may rigs on 235s and a few inches of list, much more ruggedly than just going out to the fishing hole, or to a favorite huntng spot up a Forest Road on 30's. And I have done so with a standard D30 and a D35.
Click to expand...

All good points, but the goal here is to build the truck for wheeling in the future. This buildup is only in the beginning of the planning stages, and I like to take my time and do these things right(hence all of the questions). The point I was making is that I'm not looking to cut the truck up, add an exocage, long arm suspension, 38" swampers, etc. I want it to be more capable and durable, while maintaining it's stock look and capacity for carrying humans and cargo, and it's on-road drivability. I don't have the rig or a trailer to haul around a dedicated off-roader, much less the space to store one. I tend to learn by doing, and this is a project for me where I can learn something about modifying a new(to me) type of vehicle. And who doesn't like a project? :)

If you want to spend the money on a 8.25, see it you can get one out of a 97 and newer with a tracklock installed ( look for a FS spare in the rack), and get the DS at the same time.
Click to expand...
Good info. Do all '97-> 8.25 axles from full size spare trucks have this? Is it a clutch-type LSD, or helical gear type?

tbburg said:
There might be a problem here. Are you talking just driving around, or off-roading? To get the full benefit of the truetracs, you have to learn to drive with both hands and both feet - as in, using left foot braking and/or engaging the e-brake with your right hand, while steering with the left hand and applying gas with the right foot to "lock up" the front. rear. or both diffs.(It's a technique that works with any limit slip dif, and to a small extent with an open dif, but gives amazing results with a truetrac)
Click to expand...

I know how to get the most out of an LSD, I just don't want to add the complexity of lockers with switches or any other control that I then have to explain to the better half. My concern is that she'll accidentally engage something at the wrong time and potentially damage something. The LSDs will be completely invisible to her(as they are in our other cars) when she drives, but will be there when I want or need to use them.
 
maalox said:
OK, so the front shaft stays. Maybe I'll just give it a rebuild while it's all apart. Should I be looking into a T-case drop for the rear?
Click to expand...
T-case drop is somewhat of a band-aid, don't do anything about it till you run it with the lift and know if it has a vibration problem or not. If it does, you can either drop the T-case or install an SYE, depending on how much of a perfectionist you are. Also, don't overspend on a T-case drop (I would consider $20 overspending) - all they really amount to is some longer bolts/studs and spacer plates. You can buy the hardware for less than ten dollars at fastenal/online/ace hardware/lowes, and get the spacer stock for free at any plastics fab company, just ask if you can scrounge in their dumpster for a few minutes and pick up some 1/4" and 1/2" thick pieces large enough to cut the required shapes out of. Try to stay away from acrylic and plexi, lexan/makrolon/delrin/PVC/ABS/G-10 fiberglas/resin composite are all good though.


maalox said:
Wouldn't it be better to get all of the lift out of the springs, as opposed to springs and spacers/shackles? If that's the case, I'll just go that route. I've heard about using V8 ZJ OME coils up front for a more heavy-duty application. I do plan on running an ARB Bull bar and a winch, which I know will add significant weight to the front of the truck.
Click to expand...
OME934s are (iirc) a 2" lift spring for a V8 ZJ, not sure. You don't want to get ALL the lift on a leaf spring out of the leaf, or the shackle won't be long enough to let it actually move (you'll get the most articulation and the best ride with long, flat springs and properly sized shackles), but yes, keep the coils on the front all-spring lift instead of using spacers.

maalox said:
Let's just say I have an inside guy at a Chrysler dealership, so I get all of my OEM stuff VERY cheaply. And I have access to wholesale junkyard suppliers. This is one of my motivating factors for upgrading with OEM parts.
Click to expand...
Sounds like a good reason to me.



maalox said:
I read up on the Ford 8.8, and I decided I'd rather stay with the rear axle originally designed for the truck, so I can keep my modifications internal/bolt-on. If I can find one with 4.10 gears in it already, I'll do that. I want to build at least the rear out of the truck, then swap it all in as an assembly. If I can find another inexpensive ABS-equipped D30 front, I will grab that, too, again in the interest of building it out of the truck and then swapping it in. I prefer that route to avoid downtime, and it helps me take my time and not rush through it just to get the truck back on the road.
Click to expand...
Exactly what I've been doing for the last 2.5 months, glad I did, I had a week of vacation to get it all done in and was nowhere near done, then got a piece of metal in my eye and couldn't continue for a while. Was still able to drive to work.

Zuki-Ron said:
If you want to spend the money on a 8.25, see it you can get one out of a 97 and newer with a tracklock installed ( look for a FS spare in the rack), and get the DS at the same time.

Ron
Click to expand...
We've been over this a million times... a fullsize spare does not indicate LSD, it just makes it a possibility. My 96 Sport came with a fullsize spare and no LSD. I've actually never seen an XJ with a donut spare.
 
kastein said:
I've actually never seen an XJ with a donut spare.
Click to expand...

My '92 came with a donut too, although it's been in my garage for about 8 years (once I started wheeling I bought a rim and got a full-size spare).
 
I would recommend going 31's and 4.10.

Add a locker, and you can go anywhere worth going.

And as far as the 8.25 goes, don't get one with a lsd, they wear out way too fast.
 
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