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School me on the 8.8 swap

underpowered

NAXJA Forum User
Location
cain-tukee
i have searched, but sorting through it all was a pain.

the D35 went south on my 1990 XJ this past weekend. called up the local junk yard and they want $100 for an 8.8 so figured for such a cheap price might as well upgrade.

now, i have heard many things about the swap. some say perches DO NOT need to be moved. while others say you have to get new perches and they have to be moved from teh stock location on the 8.8.

i know shock mounts need to be moved, but that is merely a minor detail.

i am not sure what year axle i am getting, won't know till it is delivered later this week by the JY. Nice having front door service from them for the same price.

all i know is it is a ford 8.8 out of an exploder with 3.55 gears.
 
I did an 8.8 swap about a year ago. You will need to remove the spring perches. They are spring under in an explorer and the XJ is spring over. Dan at ruff stuff has a great 8.8 kit with spring pads, u bolts and shock mounts.

The other thing you need to address is the rear disc brakes. I'm running two passenger side brake hoses to the calipers, and used the stock e-brake cable with a little modification and cable clamps. The rear discs work great and e brake woks good as well.

I also removed the flange from the 8.8 pinion and replaced it with a standard 1310 yoke. I'm running a front xj driveshaft in the rear and it works great, I only have to carry one trail spare since it fits front and rear.
 
well i am not sure whether the 8.8 i am getting will have disc or drums, it may be pre 95.

i should be able to make my own perches, not that complicated to make with the right tools.
 
I also did the swap recently. Yes, you will have to re-do the spring perches due to the spring over/spring under difference. I agree with the Ruff Stuff recommendation...they're stuff is stout. You will want to be sure to get the right shock mounts from Dan (Ruff Stuff) so that the shocks mount at the center or below the axle. Even with the mounts that are at the axle center, my shocks now bottom out before bump stops come into play. I cut the shock mounts from my old D35 and modified them to mount about 2" below the axle centerline. They only hang a little below the axle this way, and shocks now work properly.

E-brake mod using cable clamps worked like a charm. And X2 on using two passenger hose connections, but you have to be creative how/where to mount the hose bracket. I ended up drilling/tapping a shock mount on one side (can't remember which), but it worked out fine.

Good luck
 
i dont run a 8.8, but i have set up two to go into other peoples xjs. the perches do have to be moved. the perches on the 8.8 are easier to remove and salvage than they are on our stock axles, but i would still recommend RoughStuff perches (and cover too). i do like the JKS shock mounts better than dans though
 
well if i can't salvage the stock 8.8 perches, i will just build some. i work in an industrial fab shop so making them will not be an issue at all. and i may end up inboarding the shocks as well, stock local simply won't do, hangs much to low.

not concerned about the e-brake set up. won't be needing that. if i need an e-brake, i'll park it up against a rock or tree. it is a woods only beater Heep.
 
Sorry to jump in on this thread, i am as well getting ready to do this just for the upgrade not because my Dana failed me or anything my question is whats the easiest way to center the axle under the rig to mock up the perches? and for who have done this fab what degree did u go on the pinion angle? i was thinking 2 degrees? once again sorry for thread hacking but seems like the right thread for it.
 
Sorry to jump in on this thread, i am as well getting ready to do this just for the upgrade not because my Dana failed me or anything my question is whats the easiest way to center the axle under the rig to mock up the perches? and for who have done this fab what degree did u go on the pinion angle? i was thinking 2 degrees? once again sorry for thread hacking but seems like the right thread for it.
see what you current pinion angle is.

angle out of the T-case and pinion angle should be the same in an ideal situation. but in most cases, the pinion is angled slightly more than the T-case is.

as for preches. measuer from the brake baking plate. do side to side, then figure out how far from each side you need to place each perch. the XJ is just over 43" pad with i believe. so measure plate to plate, then subtract the 43.XXX. take what it left over, divide by two, that will be how far from the backing plate to place your perch on each side.

simple enoough. jsut be sure to weld both perches in like to keep you pinion angle correct. easiest way to do that, is to set the pinon of the axle on a jackstand at the desired angle, then use a level to set you perches and tack them on.
 
Angle depends on your driveline. If you've gone to an SYE with a CV joint driveline, then angle at the axle is 1-2 degrees below transfer case. If no SYE/CV, then driveline angle is split between transfer case angle and axle angle.

As far a centering...you'll know what to do. If your springs are still in place..then center between them..otherwise, find something else to center them by.
 
You're lucky, the pinion length on the 8.8 is apparently fairly close to that of the d35, so your driveshaft should be at least close to fitting. I'm not sure if the page I read was taking into account the length of the flange adapter (1310 sized U-joint flange adapter is Dana 2-2-1379, the cheapest I could find was $21.80 for it, from AllJeep. Wayne over there is a great guy, very easy to deal with. Note that the 2-2-1379 flange adapter doesn't support U-bolts or straps, you press the joint caps in just like you would on a front axle.)

Other stuff - it's a narrower axle than XJ stock, so make sure you aren't going to have a clearance issue between your tires/rims and springs/wheel wells, if you do, get some rims with less backspacing or pick up some wheel spacers.

EDIT: Further, for e-brakes you may want to look at Grand Cherokee (ZJ edition, I believe) e-brake cables. The end that clips into the brake housing is the same as the Ford design, and supposedly they are the right length to work nicely, though I haven't verified that part yet.
 
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Sorry to jump in on this thread, i am as well getting ready to do this just for the upgrade not because my Dana failed me or anything my question is whats the easiest way to center the axle under the rig to mock up the perches? and for who have done this fab what degree did u go on the pinion angle? i was thinking 2 degrees? once again sorry for thread hacking but seems like the right thread for it.


Here ya go, all the measurements. http://www.naxja.org/forum/showthread.php?t=1000520
 
well, back in the hunt for a rear end. JY just called and the rear was marked wrong, turned out to be a LSD 3.73, not a 3.55 as it was tagged. they have no other 3.55 rear ends at all, not even a D35.
 
I bet they don't know what they're talking about at all. If you can, walk around their lot and look at the tags on the diffs, when you find one that reads 4 10 or 4L10 (with LSD) it is a 4.10:1 geared diff, when you find one that reads 3 55 or 3L55 it's 3.55s, etc. Then just tell them which one you want.

I called about half a dozen different junkyards that claimed they had d30s with 4.10:1 gearing, all of them either claimed they had it and told me wacky stuff like "it has a 4.0L so it probably has 4.10s" or wanted an extremely exorbitant price, or just plain never called back. Some of them claimed they didn't have any, but when I looked on car-part.com they came up as having four in stock, the counter computer jockey just didn't know how to use the search page properly. I don't trust junkyards to get stuff like gearing right anymore.
 
I bet they don't know what they're talking about at all. If you can, walk around their lot and look at the tags on the diffs, when you find one that reads 4 10 or 4L10 (with LSD) it is a 4.10:1 geared diff, when you find one that reads 3 55 or 3L55 it's 3.55s, etc. Then just tell them which one you want.

I called about half a dozen different junkyards that claimed they had d30s with 4.10:1 gearing, all of them either claimed they had it and told me wacky stuff like "it has a 4.0L so it probably has 4.10s" or wanted an extremely exorbitant price, or just plain never called back. Some of them claimed they didn't have any, but when I looked on car-part.com they came up as having four in stock, the counter computer jockey just didn't know how to use the search page properly. I don't trust junkyards to get stuff like gearing right anymore.

that why he pulled the cover for me just to verify, as i said it was tagged incorrectly. the tag did say 3.55, but he pulled the cover and counted teeth just to be sure, and it was a 3.73. they guy knows his stuff
 
Ah, cool. I guess your junkyards are a bit more competent than the guys around here!

I usually use the turn counting trick, make sure both hubs can turn freely then spin the yoke and count how many times it takes to get a full turn out of the hubs.

Good luck - BTW, I think it's usually out of an Exploder as the width of the axle is closer (not sure on this one), and iirc many Rangers came with a 7.5 instead of an 8.8.

EDIT: jeeperjohn is also correct afaik. A 96 up (or 97 up, not sure) Exploder will probably have rear discs. Mine was trashed, I needed new rotors, pads, and parking brake shoes + hardware kit, but it already had the right brackets/backing plates at least.
 
yeah, i know some rangers had the 7.5.

funds right now are to tight to re-gear it, with it being the holiday and tuition time for school. if i had to re-gear i would have to wait to after teh first of the year and miss our annual New years ride. if i did have to re gear, i would probably re-gear the front to match the rear, as a lower gear is better since i plan upgrading tire sizes anyhow.

if a ranger one will work, my buddy has a 4.10 ranger he said he would give to me. but it is probably a 7.5 as it is out of a 4-banger ranger.. i will let my buddy at teh JY know to look for a ranger one as well.

sure disk will be better, but i will take what i can get really.
 
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