Installing an LSD H233B unit from Pathfinder into D21

[HRH]

So I've had the truck apart for about two weeks now for what was supposed to be the super simple operation of swapping the LSD unit I got at Pull and Save out of a Pathfinder into the D21. Originally I planned to re-gear both front and rear ends, but decided against that as after the motor rebuild I had enough power to push taller gears. Consequently, I've gotten as high as 22.31 mpg so far, which is great for a heavy 4x4.

 

After getting the two diffs out and side by side, they are identical in fitment, though the D21 diff is longer as they house the ABS unit in the pinion snout. I've already cut it off. It's been dead for a while and I really couldn't care less. It brakes just fine without it.

 

I yanked the LSD unit apart, and plunked it's housing into the open diff carrier, note if you do the opposite, you will need a spacer to take up the driveline difference as the Pathy diff is 10mm shorter and the center support bearing does not allow the driveshaft to move rearward any farther. Ideally a one piece driveline would solve this problem. Anyway, so after swapping guts, I took it to a buddy of mine who has done gear work and figured out how to set the ring gear backlash and the bearing preload. After getting that all back together, I raced home intent on putting it in!

 

Got the diff in, only to find a piece of wadded metal in the axleshaft bearing housing. Took those over to Joe's shop, pressed them on and off, couldn't find where the metal had come from, but was already there so I pressed on two new bearings and races. After getting those back, I slipped them into the axle housing (after changing the seals) and tightened them up to check for endplay.

 

It's important to note, unlike Ford axles or other domestic stuff, these bearings are packed and sealed into the backing plate. They don't get any oil from the axle tube, so pack them well! It's the only grease they're going to have.

 

I go to check the endplay, and am rewarded with .067" each side. Spec is .020ish for the first side and .008ish for the second side. Obviously something is wrong, and since I've been obsessing over the thing, I have a good idea what.

 

The Pathy I grabbed the LSD unit from had disc rear axles. Looking up the bearings at work, I find drum rear had cup and cones, disc had a roller bearing (like a Honda FWD) and the endplay spec is "0" for the disc rear end. Which explains why the center was open in the LSD unit, whereas there was a spacer in my open unit. Nasty thoughts abound and start looking for axles. Find some at Spaldings, not sure if I can just swap the axleshafts, may need the entire Pathfinder axle housing. NOT GOOD.

 

So I start thinking about this and yank apart the center diff to see about that spacer pin. Turns out it just floats in the open ring forming the cross for the side spider gears. And while at the junkyard, I find a DRUM rear LSD unit from a '99 Pathy (33 spline axles, not 31) 33 started in '96 if I remember right. I look at the bearings, and sure enough that setup is a cup and cone.

 

This is the spacer here:

 

Thus, I removed that and yanked out the LSD unit and took it apart and sure enough, the spacer dingle fits right in! I almost have it back apart but need new keeper tabs to secure the inner diff bolts. I ripped mine unstaking them from the LSD unit. Probably could put them back in, but I'd rather not as metal in the diff is bad. Anyway, I'll get those tomorrow from Nissan and then I should be able to put it back together and go have fun! Here are the rest of the pics:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[HRH]

 

 

 

 

 

 

[HRH]

I'll post pictures and possibly 4x4ing video once I get her all back together.

[thisismatt]

Nice documentation! :)

[Wide14u]

i love your threads i learn so much and i have a reference if i need it :)

[HRH]

Awww, thanks! :D Just wish I would have researched this a little more before starting the project. Have I mentioned what a pain it is hauling an 80 pound diff out from under the truck multiple times?

[datzenmike]

Good stuff. There was a site for disassembling the H-233 and adding clutches to adjust the breakaway torque of the LSD. It's gone now but we have yours. :)

[HRH]

Yeah, I stuck the heck away from doing that, I had the thing half spring open on me, but they all stayed in order. Trying to get the little keepers around all the clutches and then slide into the housing is a bit of a pain in the ass. It actually doesn't look that hard to dink with, but there are some special tools to measure the clutch packs. Didn't want to mess with it. This site has a pdf of the FSM and does go into detail on the clutches though I didn't read it all: http://www.scribd.com/doc/19272987/37/H233B

 

There are a bunch of tech specs (furnished from Datzenmike's FSM) that I'll post when I get done with this project and confirm the diff is working correctly.

[jesusno2]

Id imagine the breakaway is pretty weak on one of those even new their prolly in the 30 foot pound range.

[HRH]

Nope! They're actually pretty hard in the early Pathys. Late models got the weak breakaway torque. Checked a 4x4 forum, 90-95 Pathys are 260-280 ft-lbs breakaway. '03-'04 is 40-50 pounds. Hooray for old technology!

[jesusno2]

Id still check it with a torque wrench. I dont like pulling diffs multiple times either LOL! or i suppose you could check it in the truck to with one tire on the ground. 260 280 seems pretty high but im no expert on pathfinder lsd's thats foe sure ;)

[HRH]

Yeah, I'm not sure how I would check it out of the rig. It would be nice if I had a spare couple axle shafts and could just put a breaker bar on it. With it apart now, there's a good 1/16"-1/8" of squash when you tighten the bolts down. I'd say even with wear it's still probably in the 200 range. Figure in an automatic pathy that looked in very good condition, I doubt it got used that much. High mileage but if it's all highway driving it doesn't stress the plates much. I'll probably just wing it unless I have problems getting it back together. My gear shop wants $150 labor to reset everything, excluding parts, which clutches are probably expensive.

 

I've used old Subi diffs though, have one in the 510 and it works flawlessly despite being high mileage.

[jesusno2]

I just made a plate that fit the bolt pattern, and I was able to lock one axle in the vise. Had a buddy slide the third member onto the axle and hold it up so it didnt crash down onto the floor. Then I made another plate that bolted to 2 lugnuts that I welded a old 1/2 socket into the center of. Using a old pointer style torque wrench I was able to see what my break away was for my h190 lsd.

[HRH]

So guess what's on permanent back order? That's right, the little metal locking tabs for the bolts that hold the inner diff together. I may end up grinding the sheered areas off and reusing them, or make new ones out of some sheet steel. Or I may ignore them altogether and just loctite the bastards. They don't use them on the open diff (no clutch pressure) and the hole is open, so that would work. Still would like to have keepers. Nissan doesn't know when they'll be available, I'm sure it's not the first important thing on the ship from Japan.

[thisismatt]

You could drill the heads and use safety wire/wire locking, or get some off the shelf tab washers that could bend down against those ribs.

[HRH]

Hmm, that got me thinking, I wonder if some tooth lock washers and loctite would be sufficient. I'll bet it would be.

[jesusno2]

I used red loctite on mine works fine.

[HRH]

I'm just going to use blue loctite, and I think these 3/8 tooth washers will take the place of the locking tabs. Doubt I'll have any problem. I have ten there, two extra just in case.

 

 

[HRH]

Going to work like a charm I think. Letting it sit overnight to make sure the loctite takes. I'll go at it tomorrow hopefully get the thing back in the truck and finally get Gracie II out of my garage.

 

 

[Wide14u]

sounds like it should be fine

[HRH]

Oh, and I lied earlier. I though there were only clutches on one side. Turns out they're on both sides, but the ring gear side has the bearing pressed onto a sleeve that must connect to the spider gear. I noticed that when I was putting it back together. Slider/keepers are on both sides of the diff.

[HRH]

12:01 am. Brakes bled, fluid added to differential. Both wheels spin forward, awesome! She's on the ground, ready to be tested out for tomorrow. Probably won't take her to work, I'd like to get some local driving in to make sure everything's kosher before I drive over to Post Falls.

 

By the way, if you ever have to fill an H233B axle, they're thirsty. Took about 3.25 quarts. I actually had to add 3/4 of a quart of Valvoline in with the Royal Purple since I ran out of Royal Purple. No worries, it'll mix fine.

 

Went to Pull and Save earlier and got some axle shims. Good thing I did. I needed to remove some to get the correct end play, but had to swap in a few of the ones I pulled to get the numbers right. Really glad I grabbed both sides. Had a few .005 shims, and some .016, and .020. Between that and what was in it, got it dead nuts on. Now, hopefully I reset the differential correctly. I tend to obsess, and I worry the bearing side was a skosh tight, but it's probably fine. Ring gear backlash was perfect.

 

Anyway, I'm going to take a shower and go to sleep. Past my bedtime. See what Datsuns do to you!? ;)

[Wide14u]

you made sound like it was so easy to do tell us how it does

[HRH]

IT WORKS GREAT!!!

 

I am so freakin' happy right now! Way better. Haven't even climbed anything yet. Did some normal driving, backed up and braked a bunch because I had to adjust one star wheel to get the drum back on, and didn't feel like setting it by hand. Didn't get it too far off though. In the process, I lubed a pin that the e-brake system attaches to on the backing plate and funny thing my e-brake works better now! So win there too!

 

Drove it around, tested it in the dirt alley next to my house. Two definite strips. Weaseled around a little more, then lifted one tire and tried to break it free. No chance. I had all my weight trying to turn the free tire, didn't budge. Anyway, checked all the leakage points after that, no issues. Then went for a longer drive with higher speeds. Going up to the post office and back, I get a little chirping if I take a hard corner too fast. Not much, but just enough to know the suspension is unloaded.

 

Went up the back road towards Airway a little. No bad noises, no clunking, just smooth operation. You can tell it's locked now. I imagine in winter it's going to be a bit more tail happy, which is welcome. Previously in four wheel drive in snow, it tended to understeer. I think this will iron that out.

 

All in all, extremely happy. Felt the hubs after I got back, lukewarm, almost cool, no issues there. Checked for leaks again, no issues there. I did notice a lingering odor of gear oil, which is probably the excess venting from the vent tube. No biggee there. I'll drive it to work tomorrow and see how it does. I'm also curious to see if it's going to affect mileage. I don't think it will unless on relatively curvy roads.

[wildmaninid]

Matt, awesome swap, awesome documentation. You need to come get with me during my ka swap here in the next couple weeks, we could do a comprehensive how to