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What's involved in swapping an 8.8" rearend?


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I'm sure diggin' this site, and all the shared knowledge!

 

I'm converting an '89 Pioneer from 2 wd to 4 wd.  It's a Renix / AW4 / NP231.  My plan all along has been to do a SOA with the original Dana 30, and swap in a 4:11 ring / pinion set so it will be happier than the stock 3:56 with 33" tires.  I already have everything I need for the front suspension (adjustable upper & lower control arms and pan-hard bar, brake lines, etc)  I've found a Ford 8.8" with "bad gears" locally that I can pickup for $100.  I don't know anything else about this rearend. This will be my daily driver with the occasional desert exploration or mountain logging road.  I'm getting old enough that I don't like beating a vehicle (i.e. my wallet) to death being a knucklehead.  Since I planned on rebuilding the Dana 30 with the gear set and bearings/seals (and new spring perches for the SOA) it seems from what I've read that the $100 difference in buying this 8.8" is worthwhile.  

 

Any thoughts, words of caution or words of encouragement before I buy the 8.8 ?

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So the 8.8 is a popular swap for lots of reasons and while I have done this myself (with an AX-15 swap for 4wd and an 8.8 rear) it's really a personal preference. There are pros and cons of the 8.8 and it comes down to what you're able and wanting to do really. I'd recommend you search the DIY Index for the other 8.8 articles too:

 

https://comancheclub.com/forums/topic/48710-diy-projects-writeups-master-search-index/

 

Here's my list of pros and cons:

 

Pros:

1. Widely available in lots of different configurations (I found a 3.73 with an LSD) so finding a 4.10 is not impossible

2. Disc brakes on most of them available

3. Good aftermarket support

4. A huge upgrade over the D35 in strength

5. Debated to be as strong as a D44

6. Easy to find JY parts

7. Same bolt patters as our MJs

 

Cons:

1. ~1.75" narrower than a stock MJ axle. Some folks run them as is, some use adapters to widen them. I did the latter

2. Off-center pinion so some say this leads to U-Joints wearing out sooner with the additional angle changes to a center driveline

3. Uses a plate and flange setup so you'll need a new driveshaft setup to fit (not a huge problem)

4. C-clip axles (many don't care for these as your axle slides out if you bust an axle wheeling)

5. E-Brake setup is a little different (Lokar clips are a popular solution)

6. Requires you to weld on new perches and shock mounts vs using an MJ ready axle, like a D44 (which are hard to find)

 

I personally am very happy with my 8.8, but it's not for everyone. Good luck!

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Ditto on both replies above. I just had this done a few weeks ago. Mine is a 4:10. I found it readily in the PnP. Get a complete axel. IE brake calipers and rotors. You will need them as cores. I don't have the spacers on mine presently. The set I had was needed up front on the WJ Big Brake. I am using Canyon rims. The rear sway bar was removed on the rear. This is on an XJ. Get hub concentric spacers. That is not the brand. It is how the spacer will pilot on the axel. I bought some off E-Bay. The rear set was from Iron Rock Offroad. I haven't installed them yet. Iron Rock I think has a kit. Also, Ruff Stuff has some perches that are suppose to be for SUA. I have a set of those for the MJ, and for an ISUZU Rodeo Dana 44.  Its an odd swap, that will match the front axel I am going with.

       As for the E-brake cables, on the XJ, Morris 4X4 sells a set. I think a KJ works for latter XJs. I think the cables from a Grand Cherokee might work for the MJ. I think some ZJs have rear disk. You can look at Rock Auto and see what the lengths are. Its been a few years since I looked at that. The ISUZU has a different E-Brake setup. I think I can use MJ brake cables. Don't go done that Rabbit hole. The ISUZU is a different beast. I needed the bolt patter to match a FS GC axel, that was needed for passenger side drop.

 

     Mine has LSD. I haven't noticed any quirks while driving it. For street use, they are suppose to last. My neighbor wheeled with one for a few outings. Performance was suppose to be good. It didn't last but a few outing, or so I was told.

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@ Skorpyo - Thanks for such great details.  That helps me a bunch!  It sounds like since I was planning on new perches, shock mounts and a driveline that my $100 gets me a beefier rearend and disc brakes.  Seems like a worthwhile investment, since my time will probably be similar.

 

@ Pete M - I don't yet know what this originally came out of, but the guy I'm buying it from just pulled it from an XJ.

 

@ 75sv1 - I haven't looked up any spacers yet, but will they require new lug studs?

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If it was in an XJ it probably came out of a regular Explorer.  Verify this.  The Ranger/Sport-Trac axle is the same width but uses 27 or 28 spline axles (I don't remember specifically, but they're junk) and almost certainly had drum brakes.

 

Ask the owner to give you the companion flange off his driveshaft, along with the 12 point bolts that mate it to the pinion flange...  It will save you money.

 

The correct type of spacers will not require new studs as they bolt to the current set of studs, then your wheel is bolted to the set in them.  Example: https://www.amazon.com/gp/cobrandcard/marketing.html/ref=cbcc_pb_547314662_m?pr=con321&inc=50gc&ts=7u1o8ipnq4l75016sxy6f8v8r5sblzt&dasin=B0035HIEN0&plattr=math&place=priceblock&imp=A2QQD6IP2MNX79

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I reused my shock/ubolt plates, lokar ebrake adapters, flange adapter for the driveline (didn't need to shorten or lengthen), stayed spring under but got new longer 3 hole spring plates and shocks were still within tolerance length wise. Hardest part was the driveline angle with the spring perches. Cost me a case of beer to have it welded together. Definitely worth it specially if you plan on re-gearing. I found a 410 LSD for 100 bucks with disk brakes.

18700607_10154330396637131_682571984323587517_o.jpg

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