How To Repack a H233B Limited-Slip Differential (LSD)

[hawairish]

@SpecialWarr Hijack accepted.

 

So, as long as the WD21 differential is also an LSD unit, then you should be able to swap the side gears over.  You'll likely want to bring over the spider gears as well, but can omit the thrust block (if one).  This would basically make your WD21 diff support 33-splines.  If we're not talking LSD diffs, then no, the side gears can't be swapped, but the entire diff might be able to if the WD21 gears use 12mm bolts...I think it was tied to the use of 11 attachment studs on the housing vs. 9 studs.  I'm not sure what the cut-off was between 11- and 9-stud, might've been 1989 or maybe didn't exist on WD21 and was only a D21.  I'm honestly not sure.

 

FWIW, I've had no problems finding replacement H233B parts from RockAuto.  In fact, pretty much the only thing I get OEM are the gaskets (38320-T3322).  Not that there are many parts to replace in these diffs, but I've used National 32306C (pinion bearing & race), 32308C (pinion bearing & race), and 710195 (pinion seal) before.  Can't seem to find any differential carrier bearings I've purchased, but OE p/n is 38440-60000 which cross-refs to National KC11445Y.  Needless to say, these parts seem readily available so not sure what that mechanic is smoking.

 

As for "what else"...probably not much more.  There are oil seals at the ends of the axle tube that can be changed.  Only way to replace the grease seals are to tear down the axle shafts.  Beyond that, new gasket and fluid.

[SpecialWarr]

Thanks for the heads up and info. The WD21 is definitely an LSD ( tested on jack stands while adding a lift kit from Steve Fleury) so there shouldn't be a problem there, 11 stud vs. 9 stud is an interesting new development though....

 

My regular mechanic is not a Nissan guy per se so there are a few things that he has trouble with ( he/ they mostly work on Ford/ Chev/ Dodge/ Honda) the alignment for instance but he is across the street from where I work so the convenience factor is powerful!

 

As for me, I've never pulled off a diff, so I am completely in the dark about who's which goes where other than there are bolts and brake lines that need to come off to be able to pull the diffs out!!       Again, thanks for the info and I'll drop a line again as soon as I can get the diff out of the WD21 and into the hands of the transmission specialist and I'll let you all know how everything went.

[fj1289]

Minor resurrection here …..

 

To confirm, the ring and pinion setup is NOT disturbed when repacking the diff?  So no need to reset backlash, etc?

 

Thanks!  Awesome write up! 

[hawairish]

14 hours ago, fj1289 said:

Minor resurrection here …..

 

To confirm, the ring and pinion setup is NOT disturbed when repacking the diff?  So no need to reset backlash, etc?

 

Thanks!  Awesome write up! 

The pinion is not disturbed, but because the carrier gets pulled with ring attached, the backlash needs to be set again. Ideally you’ll check backlash first in a few spots before undoing anything so you can try to hit those numbers again (or otherwise hit within the spec range). 

[Triangles]

Wow!  Awesome write up.  I really want to repack my worthless Xterra LSD.  Sadly I can't even find used parts.  If anyone knows of a source for parts, I'd love to repack my diff.  I tried to buy a Lokka for my R200A front diff but got ripped off as they appear to just be a scam now.

[Lock]

I wanted to say thanks a ton for this write-up Hawairish. I followed this guide a lot. Couple of years ago I bought a weak Xterra center and put it in, then later took it out again, ordered some more plate and discs, and rebuilt it filling it out completely, it works amazing now.  

 

I don't know if there's a ban on posting links or companies, but I bought new friction discs and plates (and all my OEM stuff) from Amayama. 

 

https://www.amayama.com/en/genuine-catalogs/epc/nissan-usa/pathfinder/r50/1373-vq35de/power_train/380

 

Also, it was bugging me that these diffs don't have an adjustable 'ramp-angle' mechanism like a lot of other diffs and the earlier H233b models do. It didn't make sense how the clutches are engaged. I looked into it, and found a doc somewhere that said these Hitachi diffs have a 'fixed' gear setup. The side gears are cut in such a way that the more torque (axle vs center force) they encounter, the more they push away the spider gears, which in turn compresses the clutches and discs for more lock-up. Then the actual amount of lockup is adjusted by clutch discs, springs etc. which is why there's so many variations in the packing between models - and is all covered here. Excellent guide thanks!

Edited February 5 by Lock

[hawairish]

@Lock Glad you found this useful!

 

No ban on posting links.  Amayama is a great source for these and many other parts that are difficult to acquire or not available here.  In fact, I actually have two open orders with them right now.   I have purchased clutch pieces from them in the past, though at some point the supply was exhausted, particularly for the thicker pieces.  Looks like there are many in the UAE at higher/normal costs, but it's the less expensive supply from Japan that was always questionable or long lead times.

 

As for the ramp-angle LSDs, those were in Patrols.  There's not really as much of a difference between those styles and these in terms of functionality, though.  The spider gears in ours will apply outward force on the side gears to compress the clutch pack, because the clutch pack rests directly on the side gear.  In the Patrol units, the clutch pack rests entirely on those inner housings, which compress the pack when the cross-shaft ramps up on them, which means the side gears might not exert significantly on the housing (or it's a combination of both).  In both cases, there's varying outward force when differential action occurs.  Might also be the case where less, but bigger, clutch pieces has about as much friction as more, but smaller, clutch pieces.  Speculation in the absence of factory specs and dimensions.

 

That all said, I'd surely rather have the Patrol units because of the beef factor they add, but I'd be curious to know if it's a drastically better solution that what we have available.  Just another thing I wish they'd have here.