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My 8.8 Build: Young and Dumb

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8.8 swap yj
29K views 111 replies 29 participants last post by  drivertd 
#1 ·
8.8 Swap completed August 2012

Hello all. I recently picked up an 8.8 to swap into my YJ.

I want to use this thread to document progress and contribute to the already plentiful amount of info out there about this swap.

I will post updates in this thread in new posts but also go back and update one of the first 4 posts so it's easy to read

WARNING: THIS BUILD WILL BE SLOW

So we'll start from the beginning, my rig:



'90 YJ with 2.5L/AX5/NP231J and 4.10 R&P ratio.

I want to eventually run 37's and the 8.8 seems a logical way to go.

After some searching I found an ad on craigslist.
It was a guy who finds quality 8.8 rear ends in junkyards and sells them to
people doing conversions for jeeps, hot rods, etc.

I swear, he must of had 20 of these things in his garage.

I opted for the 8.8 with disc brakes, 4.10 ratio (to match my D30 front), and an open carrier (I plan on running a selectable locker).

It came from a Ford Explorer 95-01, not sure on the exact year.

The axle came with everything I could possibly need:

-All the perches and mounts still attached to the axle
-The stock sway bar
-Calipers (for cores)
-Usable rotors (could use a quick cut)
-Stock E-brake shoes
-Spring plates
-All brake lines (hard/soft and the remnants of some cables)
-Yoke
-Factory ABS sensor

I got all that for $300. It was really a pretty good deal all things considered.

So we loaded up the axle in the back of our very own Ford Explorer and drove on home.



Unloaded the axle and propped it up on the jack stands that night.



I did a quick inspection on the R&P when we picked it up and when we got it home, I cracked it open for a closer inspection



Everything was immaculate. No chips or visible signs of wear. I was very pleased.

Now onto removing the all the factory hardware.

First the hard and soft brake lines and calipers





Onto the sway bar mounts



I cut a little too deep into the axle, oops



So I filled them in with my sorry excuse for a welder (and welding skill)



Ground it smooth (and you'll notice I removed the axle breather fitting)



Next step was basically the same but with the spring perches, no pictures of this.

After all the perches and mounts were off, I wanted to pull the shafts to put in new bearings and seals.
Also to clean up the caliper mounting bracket and dust cover.

To remove the shafts, I removed the bolt that holds the cross pin in place.



Then removed the cross pin.



With the cross pin removed, you can push the shafts into the carrier enough to pop off the C-clips.



Shafts out



Now with the shafts removed, I was able to take off the caliper mounting bracket and dust cover





They come off in one piece but I later separated them.

Next step, removing the seals.
Pretty simple, just pried it out with a big screw driver



The bearings gave me a bit of trouble but I was able to get them out with some heat and a slide hammer







During this time I ordered my new bearings and seals



The next day I cleaned the inner axle tube with some brake clean and pressed (pounded) in the new B&S's using my bearing driver



Bearing in



Seal in



With the new B&S's installed I started to clean up the axle itself;

I started with the rust on the differential gasket surface:

Before



I used a 4.5" flap disc on my grinder

After



Next was just some random grinding really. I think It'll look much better this way



Smoothed out the factory plug welds, too ugly for my tastes.

I plan on welding the tubes as well before anyone freaks out about it.





Overall just smoothing everything out.

You'll notice I removed the factory ABS sensor as well. I'll need to find a plug for this later.



I went over most of the tubes, smoothing and getting off most of the grime and rust.
But you'll notice that I didn't sand down all the way to bare metal because I plan on painting the axle with chassis saver (like POR-15)
and it adheres better to rusted surfaces.

I ordered the chassis saver to paint the axle with today

I took advantage of this promo.
Ordered a Monstliner 1 gallon kit and got a free quart of chassis saver and free shipping! Unbeatable, thanks Magnet Man!

Today I also ordered the spring perches, shock tabs, and U-bolt plates.

I contacted Eddie (BESRK) at Ground Pounder Fab and we figured out what I needed. I'm very pleased so far, Eddie is a great guy to deal with. Thanks again!
 
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#2 ·
Continuing cleaning up the diff..

I ground down more of the plug welds and discovered something kind of odd..



That dark spot you see is gear oil seeping out. It was hardly anything but it threw me off a bit.

Just to be safe I got out the welder and filled in a bit



Same thing on the other side



Here's after grinding down the welds.





At the very least, it'll give me some peace of mind.

I flattened out these two ridges on the top of the diff as well



Ground down all the way



I then got out the welder again to fill in the metal that I had taken out to make it nice and smooth.

During this step I also decided to take out the carrier because of the heat from welding so close.

It probably wouldn't have mattered but, again, it's peace of mind.

All smoothed out (It'll look much better after paint)



More clean up...

Ground down the little lip on the bottom of the diff



Then went on to take off the yoke flange. Its just 4 12mm bolts that hold it on.





At this point I decided to replace the pinion seal since it was right there

Used a screw driver to hold the flange in place to I could take off the pinion nut.



I was honestly preparing to go to war on that thing but it took almost no effort to get off. Interesting...

With the pinion nut off, I just pounded the yoke off the splines



Then pried the old seal out with a screwdriver



Popped the new one in



Then bolted everything back up and torqued the nut to 100 ft lbs. Does that seem ok? I heard a few different things about the spec for just replacing the seal. Any input is appreciated.

EDIT: Finally found the torque spec for the pinion nut. The minimum torque to set the correct preload is 140 ft lbs



On to the next project; separating the U-joint from the yoke and driveshaft

EDIT: Ended up not needing this part because I decided to go with a 1310 joint on the axle side and was able to order the new flange yoke with my CV driveshaft from Tom Wood's.



I was feeling lazy and didn't have my ball joint press, so I just cut the driveshaft ear



A few minutes later and vuala



Next up was to pull the "turdy five" and mock up the 8.8 to set the pinion angle bracket positions.

I started working alone but soon a crowd began to gather..



The obligatory 'pulling the turdy' picture



Got shorter T-case bolts and got it back to stock height for the SYE.

Hold it right there, I know what you're thinking. "Why didn't you do a tummy tuck?"

Well before you ask I'll explain my reasoning..

1. It really isn't necessary for the wheeling I do right now, even though I want to do it.
2. Since I'm eventually doing the 5.3 Vortec swap, I'm trying to put as little money as I can into this engine and trans.
3. I'm getting sick of spending money...



Something seems to be missing here..



Got the springs and everything mounted up to the 8.8

If you look closely, you can see the turdy five sulking in the background..



Just the U-bolts holding everything on, the perches aren't welded.

The plan was to get the 8.8 under and still be able to rotate the pinion, didnt work out quite as planned though.



Put on another buddies' 31's so we could just roll the 8.8 under the jeep



Trying to set the pinion angle here..





I say trying because all we ended up doing was getting a pretty good estimate of the angle I wanted it at.

Which was 18 degrees..



Then we pulled the axle back out and set the pinion so that it was perfectly level aka 0 degrees.

 
#3 ·
And then put the angle finder on the perches..

17-18 degrees was about right since I wanted the pinion pointed at the output of the T-case (SYE)**

**In order for the pinion to be properly angled, it needs to point at the output of the T-case (assuming you're going to use a SYE and DC driveshaft).
I had to remove my T-case drop that I put on when I did my lift AND account for the shorter length of the SYE.
I called Tom Wood's and asked how far the AA SYE sticks out from the T-case, they told me 7 inches. It just so happens that this is where the seal on my T-case is now, so it worked out pretty well.



Then I tacked in the perches and shock mounts



I positioned the shock mounts so they'll be flush with the bottom of the axle



For those of you building along, these are the measurements I used to determine where the shock mounts and spring perches needed to be..



To get the perch dimension, I just measured from the end of the axle and the edge of the spring perch on the D35 and subtracted 5/8" because the 8.8 is 5/8" narrower on either side.

For the shock tab measurements, same thing. Measure the distance from the edge of the spring perch to the mounting surface of the shock tab on the D35. It's somewhat rough but gets the job done all the same.

Got the turdy back in to the jeep so I can drive and stopped here for the night



Next up was final welding of all the mounts and the axle tubes..



I painted the diff cover today, flame red, same as the jeep.



Also picked up the calipers and will be painting those soon as well.



Painted



Rotors turned and cleaned up

Before



After



Mmmm.. parts.



Started bending up the brake lines for the axle..



I'm going to have the soft line come down the the top of the diff.

Mocking up location of the soft/hard line connection to the caliper



Here's what I came up with



A bolt will hold the soft line to the bracket through the hole that I drilled



Welded a nut to the back for ease of access



Everything Mocked up





Caliper brackets and spring plates are ready to go:

Before



Possibly against my better judgement and as a result of my OCD kicking in, I decided to cut off all of the parking brake brackets and smooth everything out.

I figure I've never had a parking brake so why start now? Plus I'd rather have a parking brake on the driveline than the wheels.

Brackets after cutting



Sandblasted (new job is kick-***)





Finally Painted with chassis saver, I think it turned out great minus my first time spraying paint mistakes







I also got all the brake lines finished

Driver side



Soft and hard lines set. The soft line from the jeep will be relocated to drop from the center.



Began sandblasting today

Before:



After:

 
#4 ·
Plan



Measure



Cut



Clamp



Weld



Weld again because your MIG was out of gas the first time... :rolleyes:



Now Position



Weld



Sandblast



Insert plug, done



Axle is all prepped for paint



Painted...:cool:



Got the second coat of paint on



Installed the shafts and cross pin, everything inside the diff is ready to go. Crappy pics, the humidity was killing me.



Installed the caliper mounting brackets





And the moment we've all been waiting for...







Ready to be swapped :thumbsup:

SYE Install

Me "pressing" off the needle bearings of the drive sprocket thing. This is one of the points that I was worried about going into this project. It sounded confusing and I didn't have a press but once I saw what I had to work with it was very simple. Moral of the story, don't fear the SYE.



SYE mostly installed



Finished



My brake setup...I needed to extend the hard line so the soft line would come down centered on the axle. Welded a piece of angle and relocated the mounting plate for the hard/soft connection



Installed!



Pinion angle...I might shim it



Its what I get for guesstimating...what do ya'll think?
 
#13 ·
Mine's a DD too, i'm just building this axle on the side. Funny you should mention that part, I was just looking at it today. Might go that route or something else.

Just leave the abs sensor in there. It is nothing more than a magnet. Fills the hole nicely too.
The bearings are a pain to get out.

Lookin' good!
I want something more clean looking (yes its pointless really but my OCD has been kicking in). And I might end up using it as a fill hole, so we'll see.

The bearings ended up popping out easy once I heated up the tubes a bit.

Nice Job, quick question? I have a 95 YJ with a auto tranny, if i decide to do the 8.8 do i have to replace front and rear of just the rear diff? i want the 4wd to be functional.
Thanks, I'm looking to do my swap in the in a couple of weeks.

Rob
As long as you match the rear with the front gear ratio, you'll be fine.

Thanks for the comments everyone! I wasn't expecting this to be so popular.
Pressure's on now :laugh:

Here's how I'm going to update this thread, I'll post what I have done everyday in a new post but also update one of the first three posts so it stays an easy read.

So let's continue..

Today I pressed in the new bearings and seals.

I cleaned up the tubes with brake clean first and then, using my handy dandy bearing driver, drove everything in.



Bearing in



Seal in



I honestly wasn't expecting it to be as easy as it was. It took me all of 5 minutes to press in the B&S's for both sides. I'm not complaining :2thumbsup:

After that I went back to cleaning up the diff.
I ground down more of the plug welds and discovered something kind of odd..



That dark spot you see is gear oil seeping out. It was hardly anything but it threw me off a bit.

Just to be safe I got out the welder and filled in a bit



Same thing on the other side



Here's after grinding down the welds.





At the very least, it'll give me some peace of mind.

I flattened out these two ridges on the top of the diff as well



Ground down all the way



I then got out the welder again to fill in the metal that I had taken out to make it nice and smooth.

During this step I also decided to take out the carrier because of the heat from welding so close.

It probably wouldn't have mattered but, again, it's peace of mind.

All smoothed out (It'll look much better after paint)



And here's where I stopped for the night; carrier back in but not torqued. Don't let me forget to do that!

I ordered the chassis saver to paint the axle with today

I took advantage of this promo.
Ordered a Monstliner 1 gallon kit and got a free quart of chassis saver and free shipping! Unbeatable, thanks Magnet Man!

Today I also ordered the spring perches, shock tabs, and U-bolt plates.

I contacted Eddie (BESRK) at Ground Pounder Fab and we figured out what I needed. I'm very pleased so far, Eddie is a great guy to deal with. Thanks again!

One of the other things I need to get is a diff cover. I really like the look of the simple angled steel ones. Not a big fan of any logos or protruding lines.

Right now I'm looking at the RuffStuff or BTF (Blue Torch Fabworks) covers.

Anyone have any suggestions that are the same style?
 
#14 ·
Suggestion for you (I'm working on mine right now too). Either reuse the ABS sensor or get a plate to block off with a bolt. Keep it non-permanent so you can use the hole to fill with oil. If you have an SYE and have angled the axle up, if you use the stock fill hole you won't be able to get it filled to the correct amount. Use the top hole and measure the amount going it. Much easier.

I also got SUA perches and shock tabs from Eddie. Contacted on Friday, in my mailbox on Tuesday. Good stuff. Great guy.
 
#15 ·
sitedzn said:
Suggestion for you (I'm working on mine right now too). Either reuse the ABS sensor or get a plate to block off with a bolt. Keep it non-permanent so you can use the hole to fill with oil. If you have an SYE and have angled the axle up, if you use the stock fill hole you won't be able to get it filled to the correct amount. Use the top hole and measure the amount going it. Much easier.

I also got SUA perches and shock tabs from Eddie. Contacted on Friday, in my mailbox on Tuesday. Good stuff. Great guy.
I was planning on using it as a fill hole but haven't decided how exactly I want to do it yet.
I've heard of people threading the hole.. hmm.

And I think I saw your post about that, that's why I decided to go with him lol. Can't beat it!
 
#16 ·
More clean up of the axle today..

Ground down the little lip on the bottom of the diff



Then went on to take off the yoke flange. Its just 4 12mm bolts that hold it on.





At this point I decided to replace the pinion seal since it was right there

Used a screw driver to hold the flange in place to I could take off the pinion nut.



I was honestly preparing to go to war on that thing but it took almost no effort to get off. Interesting...

With the pinion nut off, I just pounded the yoke off the splines



Then pried the old seal out with a screwdriver



Popped the new one in



Then bolted everything back up and torqued the nut to 100 ft lbs. Does that seem ok? I heard a few different things about the spec for just replacing the seal. Any input is appreciated.



On to the next project; separating the U-joint from the yoke and driveshaft



I was feeling lazy and didn't have my ball joint press, so I just cut the driveshaft ear



A few minutes later and vuala



That's about all I can do until the perches and things come in.
Hopefully soon!

Btw any feedback on that torque spec would be great!
 
#25 ·
very nice! Mine is in the shop right now getting a 8.8 put on with a spartan locker and 4.88 gears and a HD diff cover. I can't wait to get the YJ back and out on the trail. It's going to be a blast.
 
#30 ·
lutzke21 said:
Sheesh, that'd be crazy tall. Wonder what my DS angle and CG would work out to be...

It's a Ruffstuff, and I'm keeping the ford flange (arrives today!). Unfortunately, I'm laid up after some minor surgery so I can't do anything today. :thumbdown:
That's a beefy cover. What did you do for a DS if you're using the ford flange?
 
#32 ·
Hmm. I'm still trying to decide what I want to do as far as DS and SYE are concerned. I'm probably going to just bite the bullet and get it all now.

And the U-bolts arrived at work today...



Too bad they wont work.

I knew they were going to be way too long but I figured I could just cut it down, no big deal. I didn't think about how long the threads were gonna be though. Oh well. I ordered some shorter ones and they should be here soon
 
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