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microfiz

Removing (replacing) rear axle and/or differential (LSD)

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Well, my rear diff seized up and now I'm thinking of replacing it. How involved is it? Planning to buy a junkyard replacement btw. Is it easier to just replace the differential or the entire rear axle? Thanks in advance.

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It'd be best to swap out the entire thing. If it sized up there could be more damage than just the 3rd member.

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If one was replacing the entire thing anyway, is there anything that would drop right in, as a j/y upgrade? Like a dana (something with more aftermarket support), or something that comes with a factory locker?

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Well, my rear diff seized up and now I'm thinking of replacing it. How involved is it? Planning to buy a junkyard replacement btw. Is it easier to just replace the differential or the entire rear axle? Thanks in advance.

 

Very easy. Jack up the axle, pull the wheels, disconnect the driveshaft (4 bolts), disconnect the brake lines at the wheel hubs, undo 4 bolts at each hub, pull the wheel hubs out maybe 6", undo 11 bolts on the diff, pull the diff. Reverse with your replacement, bleed brakes.

 

EDIT: Ooops, don't forget to drain and refill the diff. And always open your fill plug before your drain plug.

 

But to Kingman's point, if it damaged the axle shafts, it's nice having a full donor axle just in case, either for parts or full swap.

 

Since your truck is disabled anyway, wouldn't hurt to try pulling the diff first to know what you need. My donor axle cost me about $250+100 core, but donor diffs were $135+5 core through my local JYs. You'll know pretty quickly if your axle shafts are toast. It would be a good time to replace seals, too.

 

If one was replacing the entire thing anyway, is there anything that would drop right in, as a j/y upgrade? Like a dana (something with more aftermarket support), or something that comes with a factory locker?

 

Probably not. Unless you strike gold and find one with a lunchbox or ARB inside! But the factory LSDs for your generation apparently had some good numbers. Not a locker by any means, but not slouches either.

Edited by hawairish

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Also, I might be interested in some of the LSD internals on your pulled diff if they're in decent shape.

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So if LSD is not equipped then you can swap out just the gearing and the rest matches? It can't be that easy can it?

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Yes. They did a good job with the drive train on these... ;)

 

B

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Wow. On all the Chevys I worked on it was an expensive job and you needed a donor vehicle. I found 7 LSD at pick N pull. Did anyone on here make a pinned topic on what's needed? I'd go grab what I needed and just keep it to the side until I got in there.

 

I was testing out the 4x4 on the levee and it sucked having r slip and spin a tire when it was in the air before engaging the 4x4. Probably would t hardly use 4x4 if I had LSD

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So if LSD is not equipped then you can swap out just the gearing and the rest matches? It can't be that easy can it?

 

Oh, but it is!

 

Wow. On all the Chevys I worked on it was an expensive job and you needed a donor vehicle. I found 7 LSD at pick N pull. Did anyone on here make a pinned topic on what's needed? I'd go grab what I needed and just keep it to the side until I got in there.

 

I was testing out the 4x4 on the levee and it sucked having r slip and spin a tire when it was in the air before engaging the 4x4. Probably would t hardly use 4x4 if I had LSD

 

You just need to grab the third member from an LSD axle (Pathfinder or Hardbody). It's easier if you get it with the same gears; just pull your diff, swap in the new diff. That's it! No setting up gears, but you should do due diligence on the replacement diff to make sure it's in spec.

 

If you pull a diff with different gears, just need to pull both carriers out, and put your ring gear on the LSD carrier. You will need to set backlash (pretty easy). However, depending on your OE gears, you may be able to improve gear ratios, but will need the front diff of course to match.

 

I sent microfiz some instructions and pics on what to remove and how. Pretty straightforward.

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It's been over a year since I did this and I forgot to close the loop (in case someone else needs to do this). Patrick (hawairish) was absolutely instrumental to my success. I even managed to meet the legendary man face to face. =)

 

Anyway, I'll be posting our messages here since his instructions were so detailed and on point.

 

Here's the continuation of this story:

 

Me: So I was at the same junkyard yesterday (the same one I was checking out last Saturday) to pick up seats for another car. After getting the seats and loading them up in my car, I figured I'll take another look to see if I just missed the "right" Pathfinder. Well, sure enough... I did. I spotted a dark blue Pathfinder (200K on the odometer) with manual transmission, HG43 diff and disc (I guess all manuals come in this config).

I wasn't planning on a rear axle pull so I didn't have the right tools, but with perseverence and stubborness, I was able to rip it out in a few hours!

Now with this thing out, I am planning to clean it and then install this coming weekend.

Do you have recommendations on what I can prep for before installing this unit? My clutch is going out soon... I wonder if I could include this job if it doesn't take too much of my time?

So can I use my front differential to move my car into my garage so I can service it? Or is it a bad idea?

Also, after reading posts on the forum, it looks like replacing the third member might even be easier than replacing the entire rear? I just feel like removing the drive shafts could become a bigger headache. Aren't there special tools required (I'll have to go back to my Hayes manual)?

Patrick: Awesome, glad you found what you needed. Some answers/notes:

  • Moving the truck with the front diff will be fine. Pull the rear driveshaft out first...it'll slip right out of the transmission without tools. Since you have manual hubs, you may need to rock the truck while in park to hear them click after engaging them, then shift to 4H and creep in.
  • In my opinion, it's much easier to just replace the 3rd member...you'll still need to at least jack up the axle and pull the tires, but that's far easier than working the axle off completely.
  • You should plan on taking apart the donor axle anyway to check the internals for any issues, and since you'll have it apart, it'll be ready for transplanting (and it's a good way to do a dry-run of the process).
  • If you have the means (a dial indicator and base), you can also confirm that the diff is still in spec and doesn't need any adjustments. But once you've got it out, you'll want to inspect the ring and pinion for chips or odd wear patterns (you can check just by giving it some spins).
  • No special tools at all...wrenches and sockets, and maybe a rubber mallet or dead-blow or small pry bar to convince the axle shafts to come out a little. I only used an impact to save time threading all the nuts that hold the diff to the axle, but not for tightening anything, just a torque wrench.
  • There are 4 nuts on the axle tube behind the brakes...remove those, and the axle shaft is basically ready to come out after loosening/disconnecting any brake lines or cables. You'll need the shafts out at least 6" to clear the diff carrier...I found it easiest to just disconnect the hydraulic brake line (I was able to leave the e-brakes connected) and bleed things afterwards. Though...I don't know the exact setup on a WD21, since I've only worked on R50s, but it should be very similar.
  • If you plan to replace seals, then you need to disconnect the brakes and any sensor lines (not sure if it has ABS or not). Seals are cheap and pretty easy to replace.
  • Since you have the axle, makes it easy to give it a practice run. If you need some reference pics or more detailed instructions, let me know...I have an axle housing and several diffs in my garage and can show you exactly what you're looking for.
  • For other prep, it's kind of an on-the-fly process. If you trust your seals, at least give them an eye-ball. But they are cheap enough to warrant replacing. The carrier gasket (installs between the 3rd member and housing) should be replaced...sometimes it'll come out in one piece and need minimal scraping on the axle housing, other times, not so much. You'll need the mating surfaces on both diff and housing to be as clean (smooth) as possible. I just take a razor blade and gently scrape. You can get replacements from Rock Auto for cheap.
  • If that axle has an orange sticker on the rear of the axle housing, it'll have the LSD (a good find).
  • You'll need 3L of diff fluid. If it has the LSD, be sure the oil you get has an LSD additive (or you can add separately).
  • As for the clutch, that's a whole other beast. The only advantage you have going into that is that the rear driveshaft will be off, but that's really it...and it's easy to remove otherwise. Changing the clutch will be far more time consuming than change the diff. Changing the diff will probably only take 2-3 hours, wheels up to wheels down.
  • While the driveshaft is off, wouldn't hurt to give the u-joints some pivots to see if it moves smoothly.
  • The Haynes manual might be pretty generic for the process, but you may have some better references here: http://www.nicoclub....FSM/Pathfinder/. Manuals for a 92-95 will be fine for you.

Me: Again, thanks for the comprehensive help, Patrick. I've been mulling over what to do on the truck based on your recommendation. Just some questions:

  • You should plan on taking apart the donor axle anyway to check the internals for any issues, and since you'll have it apart, it'll be ready for transplanting (and it's a good way to do a dry-run of the process).

I was actually thinking that if I pull the donor axles apart that I transfer the wheel axles as well to assure that the axle splines are intact. I don't know if mine got damaged in the process of failure. Is that a good idea, or an easy one at least?

  • If you have the means (a dial indicator and base), you can also confirm that the diff is still in spec and doesn't need any adjustments. But once you've got it out, you'll want to inspect the ring and pinion for chips or odd wear patterns (you can check just by giving it some spins).

I don't have a dial indicator... just a caliper. What exactly am I measuring for in the differential? Flatness?

  • For other prep, it's kind of an on-the-fly process. If you trust your seals, at least give them an eye-ball. But they are cheap enough to warrant replacing. The carrier gasket (installs between the 3rd member and housing) should be replaced...sometimes it'll come out in one piece and need minimal scraping on the axle housing, other times, not so much. You'll need the mating surfaces on both diff and housing to be as clean (smooth) as possible. I just take a razor blade and gently scrape. You can get replacements from Rock Auto for cheap.

Can I use the liquid gasket maker in place of a paper gasket? I may not have time to get one (I can always try a stealership).

Again, I can't thank you enough. The work itself doesn't seem to complicated, but it is labor-intensive. =)

Patrick: No sweat man, glad to help.

So the best part about having a donor axle is that it definitely doesn't hurt to upgrade or swap over parts, and everything should be a perfect fit. Really the only things that should be kept together are pretty much everything on the 3rd member. I'd expect your axle shafts to be fine (you'll know pretty quickly when you try to slide them out), but yes, if you suspect any issues, you can swap them easily. Swapping over the brakes should be pretty simple, too.

A dial indicator allows you to check two things, actually, and one is pretty critical to differentials: backlash. There needs to be a precise amount of play between the pinion and ring gear...not too small that it causes the gears to bind, and not to big that it allows the gears to slop and chip. It's not something you can generally feel out (without experience...but even then, those guys always measure). It's really only critical when you start taking apart the carrier, which you won't need to do. But, usually for peace of mind, it's just one way to check that the replacement is in spec. The other use is to check gear run-out, where you're making sure the ring gear isn't warped and that the carrier is rotating 90° to the pinion. But again, in your case, it's just a way to confirm that the donor is in still in spec (which it likely is).

You can use a liquid sealer, just check on cure times before filling the diff with gear oil. The other thing is that the angles on the axle shafts take into account the thickness of the paper gasket (it's actually a metal gasket with paper surfaces). You'll be able to get the axles to slide into the carrier with a liquid gasket, though, so it's not a big concern, but something to think about.

One other thought...removing the 3rd member from the axle. Since you've got the donor axle off, you can practice this, but you'll need to remove the 3rd member at a particular angle, otherwise it wedges against the studs. Pretty easy to remove while not under the truck, but it's definitely a challenge when you're lying on your back. I was able to get it off and back on by myself, but it's some work. If you can get a 2nd set of hands, and maybe even a floor jack, you're much better off. It's a very heavy and awkward piece. Heads up.

These are the bolts that hold the axle shaft to the housing. Just remove the 4 nuts and give the backing plate a couple light taps from a mallet. You only need to pull it out a few inches.

IMG_3738.jpg

IMG_3739.jpg

At this point, you could slide the axle completely out if the brakes are disconnected. But as you can see, that's about all you need to clear the carrier for removal. If you have any issues pulling the 3rd, try pulling the axle out a little further (ask me how I know!)

IMG_3740.jpg

The brown ring is the gasket. It should come out in (mostly) one piece. If any of the 11 studs are loose, you can just thread them back into the housing...or replace them using studs from the donor.

Another shot of the bolts that hold the axle shaft to the housing. Yours will look a little different because of the brake backing plate. If you look inside past the gear looking things, you'll see some waxy looking stuff...that's the outer grease seal. Try to leave the grease intact if you can, but it might come out in chunks, or may stick to the axle housing, as shown...

IMG_3745.jpg

IMG_3747.jpg

That white/yellow ring is the inner seal...the black rubber seal is what you want to check for rips and consider replacing. Resting the axle on the seal isn't terrible, but obviously you don't want to leave it like this too long.

The removed 3rd member looks similar to this. You'll need to clean up the mating surface around the diff, of course.

IMG_3741.jpg

This is a limited slip, but the open diff might look pretty similar. Nissan had a couple open diff styles. If you look above those two gold-ish looking teeth, that's where that thrust spacer that MY1PATH mentioned would be (it's not on this one). Since you've got the same donor axle, whether it's there or not, it'll fit your axle.

IMG_3744.jpg

You also want to inspect the front and back of the teeth on the ring gear. You're looking for a crescent-like shape in the center of each tooth, and no chips on any teeth. Also look further down at the pinion's teeth, too.

If it's an open diff (it'll look like that only a bit flatter), you can turn some of the inner (spider) gears to check their condition, too. Again, looking for chips, cracks, or other signs of odd wear.

If you want to confirm the gear ratio without counting teeth, it'll be stamped on the side of the ring gear as XX:YY (that "32" painted below is something else).

Here's what the newer styles of open diffs look like, but they may have been used on older gens too:

IMG_3743.jpg

Piece of cake, right??

Me: Wow.... I think it took me at least a couple of hours just to harvest the donor diff (and I had air tools!). Started at 2 and didn't finish until 10 (that's with some breaks, dinner, and a run to the parts store for brake fluid... I ended up removing the drive shafts completely). Anyway, it was successful! I followed your instructions to the tee and everything went smooth. I didn't even need to use any bro points to get a second set of hands. LOL!

But the damaged diff was totally toast. Actually, I had a hard time moving the truck to my garage due to the binding parts. I'm glad it didn't damage the carrier.

Well that's it, man... I really owe you a lot. Your instructions were golden. Thanks again, Patrick.

Here's a picture of the culprit.

http://www.pinkbike....photo/12672137/

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p5pb14157976.jpgp5pb14157975.jpgp5pb14157980.jpgHere's how the old girl looks like now after a year:

p5pb14157981.jpg

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Ron, good to hear from you, and glad everything is still working! Interestingly enough, I was just up in Alameda a few months ago dropping off some axle shafts and diff parts, then came home with yet another set of WD21 disc brakes. Seems every time I travel up there or back, I'm hauling axle parts.

 

But I just finally put those brakes to use...installed them on my R50. Thanks again for the hook-up!

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Ron, good to hear from you, and glad everything is still working! Interestingly enough, I was just up in Alameda a few months ago dropping off some axle shafts and diff parts, then came home with yet another set of WD21 disc brakes. Seems every time I travel up there or back, I'm hauling axle parts.

 

But I just finally put those brakes to use...installed them on my R50. Thanks again for the hook-up!

 

Haha! Thanks again Patrick.

 

Man, I owe you at least a half dozen rounds. Let me know if you're in the area and we can talk shop. Yep, she's still running strong (her previous owner called her Helga)... currently at 261K and with new shoes ($50 wheels I got from CL and spray painted black and brand new Chinese-brand tires for $430 out the door) and ridiculously bright LED light bar. Really digging how she looks right now.

 

Read your write-up on the disc conversion... you sure know how to pick your projects! =P

Edited by microfiz
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This thread is literally is gonna save me so much trouble when doing this to my rig. Thanks dudes!

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This is an excellent write up! Planning to swap the LSD rear end from my totalled 02 LE into an 04LE with an open diff. This write it saved me much hassle. Thanks again fellas.

Josh

 

Sent from my XT1254 using Tapatalk

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so, I have a 1987 2 door pathy 5spd 4x4 with an open diff. I went to the junkyard and picked up a full rear axel with rotors and a nifty lsd.

 

my question is can I just install this without changing the pinion gears? is the n/a front manual diff compatible with the 1995 lsd?

 

I think my front is the 189(I think) and the new one is the h233b, but don't quote me

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Front should be either an R200a or an R180a, rears should all be H233b. It's the gearing that matters, though. Did you check the tag in the engine bay on the donor? Should be either HG46 or HG43. If the donor doesn't match yours, then you will have to change gears.

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Be sure to get the correct gear ratio! There were two I believe - 4.36 and 4.63. Rock Auto also offers a 5.13 for these, but I am not sure if that was a factory optional ratio or not.

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