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Discussion Starter #1 (Edited)
Lokked and Dropped


Warning: Very thorough and a lot to read. Many of the steps were easier said than done, so I tried to elaborate on my technique and what did and didn't work for me.


The Lokka install is often coupled with diff drop bushings, seeing as the differential will already be removed. Phrog Man has an awesome write up on installing the diff drop bushings. I will add a few of my thoughts throughout the process, but still recommend checking his tutorial out for a more thorough walk through specific to the bushings. I will also go into the differential tear down and install of the Lokka gears. Special thanks to cmilano for his help in getting this done. I am dividing the “How To” into 4 phases:


1. Removing Differential
2. Removing Stock Bushings
3. Installing the Lokka
4. Reassembly


Original diff drop DIY


http://www.clubxterra.org/forums/showthread.php?t=31336


Lokka


http://lokka.com/site/


Diff Drop Bushings


https://www.4x4parts.com/nissan/front-differential-drop-drown-bushings-p-5272.html


Removing Differential


The differential assembly is held in by 4 mounting bolts. It is also bolted to the CV axles on each side, and the front drive shaft. I drove my Xterra up on ramps to get more room under the truck to move around. Remove any skid plates that may be blocking access to the differential area.


The first step is to tackle the front drive shaft bolts. There are four bolts and four nuts holding the drive shaft U-joint to the differential. Put the transfer case into 4hi to lock the drive shaft from rotating. My hardware had red Loctite on them, and was extremely tight. Spray PB Blaster on the hardware and let it soak for a minute. Use a rag to wipe up any remaining drips of PB Blaster. Use a propane torch directly on the nut side of the hardware to heat the nut up enough so you can break it loose. It is a good idea to keep a spray bottle of water nearby incase the PB Blaster flares up. Use a 14mm wrench to crack the nut loose, and remove the nut and bolt. Return the transfer case to 2hi so you can rotate the drive shaft to access another bolt. Return the transfer case to 4hi to lock the drive shaft, and repeat. If the bolts still won’t break loose, use more heat. I had to keep the torch on the nut for what seemed like minutes. Tie off the drive shaft to support it after all hardware is removed.





The CV axles are next. Each CV is held to the differential by 6 bolts, arranged in 3 groups of 2.





These bolts had blue Loctite on them but can be broken loose with a 12mm wrench. You need to lock your hubs to keep the CV axle from rotating when you put the wrench on it. If you have the stock auto locking hubs like I do, they will lock after a small amount of rotation. You will need to unlock your hubs to rotate the CV axle to access the other bolts. If you have the stock hubs you need to remove the outer hub with a 6mm hex wrench to rotate the CV axle. Re-install the outer hub to lock the CV axle in place. The outer hub should slide on smoothly all the way. If it doesn’t install completely, remove and try a new spline orientation. The hubs have to be aligned properly to completely sit flush on the rotor. Repeat until both sides are completely unbolted. This can be tedious due to the amount of space you have to turn the wrench. Tie up the CV axles to the UCA to support them.

Note: If you have an impact wrench with an extension and a wobble joint, this will be a much faster task by removing the tires and going through the control arms with the wrench. Much quicker and easier.





There are four bolts supporting the differential assembly. There are two on the cross member near the drive shaft, and two in the front right above the center link. Spray the nuts with PB Blaster and let them soak. I was able to break the cross member bolts free with a 17mm socket with a breaker bar. A 17mm wrench is needed to hold the bolt head on the other side. I had to use the propane torch on the front two mounting bolts. Once again, with care, direct the torch flame directly at the nut. When it is hot enough, use the 17mm socket and 17mm wrench to break them free. Loosen all of the nuts, but leave the bolts in to hold the assembly up.

Alternative: You can also leave the two front bushings bolted in place, and unbolt the entire front cross member that the bushings attach to. This will make reassembly much easier since you would be able to lift the diff straight up into place instead of lifting at an angle.


Use some pliers and a screw driver to remove the breather hose and clamp. This is on the front of the differential behind the oil filter.





The differential is now ready to be dropped down. I used this time to back the Xterra off the ramps, so there was less distance for the differential to fall down on me. There is no real delicate way to do this, but I used a hydraulic jack and a couple of jack stands. The bolts were easy to tap out of the mounts, but it is difficult to gracefully lower the differential assembly down. Stay out from under this thing unless you have an extra set of hands. It is an awkward shape with no really convenient center of gravity. The drive shaft side ended up dropping down first, and the rest of the differential assembly followed.





Removing Stock Bushings


The first step to installing the diff drop bushings is to remove the old ones. There is one bushing on the differential case, two on the attached cross member, and one still attached to the front of the vehicle frame. Remove the bushing from the frame with a 17mm socket so you can have all four bushings on a bench.





Remove the cross member from the differential housing using a 17mm wrench. Find your weapon of choice, and work on removing that rubber! I used a drill with a slow cutting speed close to the edge of the bushing. This seemed to rip the rubber off the outer metal sleeve, destroying more rubber in its path. I then used a propane torch to heat up the rubber making is softer, and went to work with a screw driver picking away at them. There is no science to this…however you want to destructively remove the rubber is up to you.








Once you remove the rubber core you need to get to work on the outer sleeve. Use a reciprocating saw or hack saw to cut a slot in the steel sleeve. With the sleeve having a slot cut into it, you should be able to take a cold chisel and hammer the sleeve out. It works best to turn the chisel at a 90 degree angle to the wall and try to push it down with the corner of the chisel. Cutting the slot seems to relieve enough pressure for it to slide out. If you bend the sleeve inwards, it tends to bind up and make it tighter...I tried that first and it took forever (photos below). Cut one slot and see if it slides out with a few hammer taps around the outer edge. I was able to remove one that was not bent or deformed at all, which is what I would recommend trying to do.







Note: Trying to bend the bushings inwards like this photo tends to bind up and make it more difficult. Cut one slot, and try to push straight down on the sleeve around the edges.


We will install the drop bushings as the last step before re-installing the differential…so you are now ready to move on to the Lokka!
 

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Discussion Starter #2 (Edited)
Installing the Lokka

Now that you have the differential removed from the truck, you can open it up and begin the differential tear down. First, drain the fluid using your method of choice. Remove the differential cover using a 14mm wrench.



On the driver’s side axle, there is a single 14mm bolt to remove. Once you remove this bolt, you can remove the short axle.



The passenger side has a flange connected with 4 bolts. Mark the flange and remove these bolts to slide the long axle out of the differential housing. You may need to give it a few taps with a dead blow hammer or rubber mallet.



Now you are ready to remove the bearing caps. Use a 17mm wrench to remove the 4 bolts holding the bearing caps in place.



Use a pry bar behind the carrier and pry it out of the casing. I had to use a 3 pound hammer to tap it out by prying against the back of the carrier and the edge of the casing. When the carrier comes out, keep track of the parts that come out with it. Make sure you note the orientation of the bearing caps and which side each of the washers go back into. You will also have a spacer on one side to keep track of.





Now that the carrier is removed, mark the ring gear. Use a 17mm wrench to remove the bolts holding it in place. It can be difficult to remove the torqued bolts unless you have a bench vise to hold the carrier in place, or an impact wrench. I ended up marking my ring gear by putting a bolt back in the hole that lined up with the cross pin in the carrier because my sharpie kept smearing.



With the ring gear removed, take a 3/16” punch and a hammer to slide the cross pin just far enough so the cross shaft is free. I punched the pin from the ring gear down, but I am not sure if it can go either way. I was able to use the blunt end of a 3/16” drill bit as a punch, since the punch I had was tapered and would not push the pin down far enough.

If you use a normal punch, watch the tapered section where it starts to get wider. You don't want to get it wedged in the hole. If you do, then you will need a smaller punch to punch your punch out of the hole (personal experience). The pin is actually hollow, so make sure the punch seats against the edges of the pin to drive it down.



With the pin out of the way, remove the cross shaft and the two spider gears that rotate on it. These gears (and washers) are no longer used.



Now the two axle gears can be removed. Make sure you keep track of the washers on each gear. They need to stay on the same side that they came from. The driver’s side axle gear will have a special nut pressed into it. Remember that single bolt you removed from the axle shaft? This is what it screws into on the inside of the casing. Take a socket and a hammer to knock it out.



This nut will need to be inserted into the Lokka axle gear. Inserted as is, you will not have enough clearance to install all of the gears into the carrier “window”.





You need to grind the flat edge down with an angle grinder and remove about half of the width.

Warning: The nut will be VERY HOT from the friction of grinding. Use gloves, or let it cool before continuing.



NOTE: It was brought to my attention you can install the gears without grinding down the nut. From clubxterra mmetzger1234:

Just did mine. DO NOT GRIND DOWN NUT! This can cause the nut to fail under load. then destroying your diff. Put both axle gears in first then, Nut can be place inside the correct side spacer with cam gears. then flip carrier on side to press nut in axel gear through axle gears hole after both sides are in the carrier. Everything should fit fine.
Once you have grinded down enough (hopefully) of the nut, grab your Lokka gears: You should have two axle gears, two spacers, and two cam gears.



Take the nut and press it into one of the Lokka axle gears. I used a 17 mm socket and a hammer to mate it into the splines.



Next, take some grease, and seat the washers against the backside of the axle gears.



Now you can insert both Lokka axle gears into the carrier. The one with the pressed nut should go on the side with the shorter axle. Put the spacers in the middle of the cam gears with the flat side going inwards towards the middle of the carrier. Apply some grease to the gears, and if you are lucky, both cam gears will squeeze in the carrier window, and the grease will stick the gears in place. If the gears don’t fit, you will need to grind the nut down some more. If you need to grind the nut some more, obviously, remove it from the gear so you don’t grind your gears by accident!



Now, line up the holes and slots so you can insert the pins and springs. The pin goes into the hole with the flat end at the bottom of the hole and the nipple pointed at the slot. You have to tap the pin into the slot first (punch and hammer), and then slide it down into the hole (I used a small hex wrench to push it). Next, pop in the springs. Start by putting one end of the spring around the nipple of the pin. Then, compress the spring enough to seat the other end in the slot. Once again, I had to tap them in with a hammer and punch to fully seat them in the slot. This was tedious and a little difficult, but be careful, and don’t lose a spring when they pop out and go flying!

 

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Discussion Starter #3 (Edited)
Reassembly

Rotate the Lokka so the cross shaft can be inserted and retained with the pin. Use feeler gauges to take the measurements as included in the Lokka instructions, and assuming your measurements are in spec, continue to reassemble the differential. You will need a dead blow hammer or rubber mallet to seat the ring gear on the carrier, then you can tighten the bolts in a star pattern to fully seat the gear.

Before reassembling the carrier into the differential casing, I recommend spraying brake parts cleaner in the casing and wiping everything out with a clean shop rag. Also, apply some fresh grease to the bearing races and spacers. Assemble the carrier into the differential casing, using care to assemble the washers and the spacer into the proper place.



Insert the two axles, and bolt into place. Check your differential cover gasket, and replace if necessary. Make sure your drain plug is in place. I recommend using Teflon tape on the plug threads to maintain a solid seal. Fill with fresh fluid (1.75 liters…1.85 quarts), and put the fill plug in place.



Torques

Ring Gear: Medium thread locker
Bearing Caps: 65-72 foot pounds
Short Axle Bolt: 25-33 foot pounds
Long Axle Flange: 23-31 foot pounds
Differential Cover bolts: 29-36 foot pounds

Now, bolt the cross member back to the differential casing. Go ahead and pop the new bushings in place. This is easier said than done, as they are a tight fit and will need to be hammered. The hole goes at the top on the bushings attached to the differential cover and cross members. The single bushing on the extra bracket has the hole on the bottom.





Loosely bolt up the bushing on the bracket to the frame. Loosen the bolts holding the other bracket to the frame. This helps you get those first bushings in place.

Use a strong friend, a jack, etc to lift the front of the differential into place. You have to put the front end almost straight up, and rotate the front bushings into place on top of the frame as you bring the drive shaft end up. I was able to do this myself, but had modified the scissor jack to turn it into a steel platform to support the differential. I had to continually shift jack stands around and try to inch it into place. This is a complete PAIN.

Alternative: If you removed the entire front cross member, you can lift the entire differential straight up with out having to rotate it into place.





Insert the bolts that are first available (two front bushings). Hope that the cross member bushings don’t need readjusted. I got the first two bushing bolts in, and had to use a pry bar to help seat the cross member bushings. My cross member bushings were ever so slightly off, and was unable to get the bolts back in. I ended up replacing the cross member bolts with the metric equivalent (M12 X 90) as they are slightly more narrow. Use grade 10.9 if you go this route.

Reassemble the CV axles with medium strength thread locker and bolt up the drive shaft. The drive shaft can telescope, and may hydraulically retract, increasing the gap between the drive shaft and differential. If that is the case, try to get one bolt started and wrench it to force the drive shaft to extend. This should bring the flanges close enough to seat the remaining bolts.

Reattach the breather hose. Perform the Lokka test included in the instructions.

Torques
Cross Member to Differential: 50-64 foot pounds
Bracket to Frame: 50-64 foot pounds
All Bushings: 50-64 foot pounds
CV Axles: 33 foot pounds with thread lock
Drive Shaft: 64 foot pounds

CONGRATULATIONS, YOU ARE NOW LOKKED AND DROPPED
 

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Good job!!! These instructions will make it very clear for a DIY guy to accomplish this install at home. You wont be dissapointed with the traction you just gained!
 

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great write-up, I'll be using it soon. Thanks!
 

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Did you measure the clearances like the installation instructions call for? It seems a little unclear where exactly to measure.
 

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Just did mine. DO NOT GRIND DOWN NUT! This can cause the nut to fail under load. then destroying your diff. Put both axle gears in first then, Nut can be place inside the correct side spacer with cam gears. then flip carrier on side to press nut in axel gear through axle gears hole after both sides are in the carrier. Everything should fit fine.
 

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Discussion Starter #8 (Edited)
I did measure the clearances with feeler gages...You have to have everything installed, and measure how close the cross shaft is to the flat edge of the spacer. Very little gap.

The other one is the inner-cam spacing, which is between the flat surface of each cam gear, which is larger. Basically, the center gap after everything is installed.



Also, thanks for the feedback on the axle gear nut. I didn't think to leave it loose in the spacer and press it into place after installation. I updated the How-To to include this step.
 

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Did you have to reuse your old metal sleeves from the bushings Rob?
 

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Discussion Starter #10
I purchased the steel sleeves from 4x4parts.com with the diff drop bushings

On a side note, if you haven't already gone too far...don't do the diff drop...

waste of time and no real benefits
 

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Too late now!!! Haha guess I'll have to live with $45 less in my pocket
 

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FYI, ring gear bolt torque is 96-106 or so.
 

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I purchased the steel sleeves from 4x4parts.com with the diff drop bushings

On a side note, if you haven't already gone too far...don't do the diff drop...

waste of time and no real benefits

The diff drop relieves the CV angles at full droop...that's a real benefit.

Guys who don't do it have proportionally more CV issues.....its just physics.

So, It IS a Royal PITA, so, if you'd rather be under the truck on a trail doing CV's, etc....sure, people can do that instead, its a free country.

A small drop in the diff makes a large difference in the angles, which helps to compensate for added droop from new UCA for example.

So, sure, you can take out the diff, swap in the lokka, etc, and put it back without a diff drop, and the lokka and truck will work exactly as it did before.....but, its one of those "While you're at it" things that makes sense to include "While you've got the diff out anyway".

:D


I can definetely see skipping the diff drop if you are not adding any wheel travel/droop though...as the point of return is at play.
 

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Doing mine right now and am wondering if anybody else has run into this.
My front cross member along with 4 big bolts is tack welded to frame.
This is obviously from the factory.

Anyone else's like this?
Gonna just grind it loose but wondering if anyone has seen this or has any incite why it's like this.
 

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It is not necessary to remove the front crossmember to get the diff out. Mine was not welded, but the bolts were so damn tight and difficult to deal with, I just left it in place and removed the differential at the bushing locations. This makes it more difficult to reinstall, but I did it by myself with a jack, a piece of rope, and some brute force.

I wouldn't bother cutting it loose if you don't have to. That is odd they'd weld it in, but perhaps it made the mfg process work better.

Incidentally, something I noticed the other day: be careful with your auto hubs. I was on the beach and disengaged my 4WD and rolled backwards a couple of times, but apparently my right hub did not disengage. I then drove about 20 miles like that. Fortunately, very few turns, but I was going about 60mph for a lot of it. I noticed something was wrong when I heard a bit of a squeak and ratcheting when I pulled into a parking lot to get lunch. I did some driving around in the lot, and could tell my front shaft was turning, and the right side would ratchet in a tight turn. I backed up a few times and got it to disengage without having to remove the hub itself and manually disengage it. Fortunately, there is no sign of drivetrain damage.

I was thinking about manual hubs anyways, and this sort of sealed the deal on that decision. I looked for some used Pathfinder or Hardbody manual hubs, but even despite being in one of the used part capitals of the nation here on the northside of Houston, I can't find some without some serious effort. I got lazy and ordered some Warn premiums. People fuss that they might break, but IMHO, I think they're engineered to break before your other components do.
 

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Their really just tack welds, gonna grind them out and forget they were ever there.
(found others who did this)
I've contemplated Warn hubs myself. Gonna disassemble and regrease mine but gonna keep an eye on them too.
 

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Discussion Starter #17
It is not necessary to remove the front crossmember to get the diff out. Mine was not welded, but the bolts were so damn tight and difficult to deal with, I just left it in place and removed the differential at the bushing locations. This makes it more difficult to reinstall, but I did it by myself with a jack, a piece of rope, and some brute force.

I wouldn't bother cutting it loose if you don't have to. That is odd they'd weld it in, but perhaps it made the mfg process work better.

Incidentally, something I noticed the other day: be careful with your auto hubs. I was on the beach and disengaged my 4WD and rolled backwards a couple of times, but apparently my right hub did not disengage. I then drove about 20 miles like that. Fortunately, very few turns, but I was going about 60mph for a lot of it. I noticed something was wrong when I heard a bit of a squeak and ratcheting when I pulled into a parking lot to get lunch. I did some driving around in the lot, and could tell my front shaft was turning, and the right side would ratchet in a tight turn. I backed up a few times and got it to disengage without having to remove the hub itself and manually disengage it. Fortunately, there is no sign of drivetrain damage.

I was thinking about manual hubs anyways, and this sort of sealed the deal on that decision. I looked for some used Pathfinder or Hardbody manual hubs, but even despite being in one of the used part capitals of the nation here on the northside of Houston, I can't find some without some serious effort. I got lazy and ordered some Warn premiums. People fuss that they might break, but IMHO, I think they're engineered to break before your other components do.
I have had the SAME thing happen with my auto hubs. I have cleaned them out thoroughly to get all the gunk out of them, but they still get stuck randomly and refuse to disengage. Sometimes they randomly stick and engage at times.

I wonder if these hubs have always done this, but with an open diff, I never realized a hub was stuck. Having the Lokka forces the one stuck hub to drive the other side which makes all sorts of random clunky noises on pavement.

Agreed...this sealed the deal for me to get manual hubs.
 

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Ok doing this myself today.
Got it dropped out and taken apart to the point of removing pin to drop spider gears out and I notice this......





The spider gear pin has two flats 180deg apart all the length of the pin.

This is normal?
 

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Anybody?
I don't remember reading or seeing this before.
 

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Frog, I had mine apart yesterday...mine was like that.

Rob, thanks for the write-up...it helped tremendously. I was able to drop the front crossmember and it seemed to make things pretty easy.
 
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