The Spartan Locker ?

I’ve been studying and I’m starting to understand the whole concept now, what would we do without YouTube. I didn’t want to hijack anyone’s thread so figured why not just start a specific one for these type lockers.

So I have a few questions for you guys that have done it, I’m thinking fall when it cools down I’m going to do this mod along with some sliders for good measure.

On the install for the rear, anything else that should be done while the axles are out, such as seals, bearings ? How long did it take from turning the first bolt until replacing the last IF that was the only thing done.

Does the front axle need to be done ? Or is the vacuum controlled unit pretty much Act like a locker ? In 4 wheel drive mode.

And Thank you for taking the time to share your experience.

 

Will be following as we are looking into doing this too on our 4x4 gen 2 5speed. My question is do we need a 7.5 or 8 inch?

 

8" for the rear 7.5" for the front. Here's some pretty good info. https://old.lcengineering.com/LCTechPages/DIFFERENTIALTOYOTATECH.html

 

Here are my thoughts.

I would do the rear first, if you are not sure if you need a front locker you probably don’t. Without a front locker and in 4 wheel drive you still have an open differential, which allows the wheels to turn at different speeds and that allows you to turn and steer. With a front locker it is very difficult to turn the steering wheel.

The locker part numbers are different for the 3.0 and the 2.4, make sure you know which differential you have.

The rear locker installation is straight forward, I found the hardest part is lifting 3rd member in and out. It is quite heavy, for me at least. A floor jack a second set of hands for balance worked for me. Toyota uses a paper gasket, but the new one I received was dried out and had shrunk and tore around most of the studs. I used Hylomar gasket sealer and it leaked, so I cleaned the outside up and sealed it with Silicone gasket sealer and it hasn’t leaked in 10k miles. I would hesitate to use Silicone on the faces, it won’t leak but it is very difficult to separate, once it has been assembled with silicone. Maybe someone has a suggestion for a sealant. My axle seals were good and so I did not replace them.

Here is how I installed the locker.

Measure the backlash in 3 or 4 locations on the ring gear and write it down.

I marked the caps and adjusting nuts with a center punch. You want to install everything back to where it came from.

Loosen the cap nuts and count the turns of the adjusting nuts. Mine was like 6 turns and 5 holes on one side. Count the turns on the other side and write them both down.



Remove the caps and keep the outer races with the correct side caps.

Clean everything with clean solvent. That includes the parts left on the vehicle.

Inspect the bearings and gears for any damage.

Mark the spider cover to the carrier and remove the cover and the cross bar and spider gears, side gears and and thrust washers.



Install the Spartan Locker and OEM cross bar and side gears.




Reassemble. Recheck the backlash. If is is the same and in spec you are good to reinstall. My backlash was too large by .001, so I had to loosen the adjuster nut one one hole on one side and tighten the nut one hole on the other side to move the ring gear closer to the pinion. That took .0015 back lash out and I was in spec.

It took me 3 days but I was not in a hurry. It takes a lot of time to get everything clean.

 

Thank you JTM, that is very much appreciated. I’ll admit in my 40 years of wrenching on my own stuff the most intimidating thing for me is the differentials, and that’s just because I’ve never had to deal with one. The backlash thing kinda scares me.

My guru is now to old to help me, my grandfather is about to hit 103 and I can’t lean on him for the help like I used to, he taught mechanics for 30 years after WWll. Without having experienced Hands to guide me I don’t think I wanna take a chance here. As you mention, because of the weight it’s not the place to make a mistake ya know.

I’m thinking now maybe I’ll pull it, and both my driveshafts and take them to Dans Driveline and have them replace u-joints, balance my driveshafts and install the locker then I’ll just put it all back in.

For sealant I think it’s Fel-Pro that has that new pressurized can of gasket maker, brown in color, I’ve used that now in a few places and it seems to be holding up really well so I’d probably go that route and the oil recommended in some previous posts.

So I’m going to give them a call and see if I can set something up, Thank you for sharing that.

 

I would not put one of these in the front axle because you will not be able to turn the vehicle when you are in 4WD and the pneumatic axle engagement system (ADD) has locked the long side axle shafts together. I had an ARB on both ends of my Range Rover and I rarely used the front except when going straight up a really steep incline in Moab for example. With both locked and trying to turn on slick rock in Moab it was impossible. However, if you are a mud bogger or are running in deep sand or snow then this is a different story. Although you still cannot turn very well in deep sand at Pismo with an ARB that is locked in the front axle. But if I had my choice I would ARB the front as you could then select when it was to be locked. But perhaps a Grizzly or torque sensing diff might be a cheaper choice for the front? Being that it is a 7.5" ring gear it is small and don't forget the CV's are not the strongest part of the drivetrain so all this needs to be kept in perspective.

The added rear axle drive-line slop does take some getting used to with a Spartan in a 2nd Gen as the interaction between the side gears and the lockers hubs does add to the overall backlash of the rear end. This can be a bit crummy when you are at that transition point with a manual transmission in a slow corner and are trying to get the locker to not be locked and the idle speed gets a bit vague as it does with OBD 1 EFI. If you get it right you get nice clicks and differentiation. If not the unweighted tire will be screeching on the pavement and leaving black proof that you indeed have a Spartan in that rear axle. But the flip side of this is people looking at your 3VZ-E powered 2nd Gen chirping at the limit line paint as you go through intersections and accelerate out of them. This always puts a smile in the right place on my face!...

Just be sure if and when you do the install to make sure the thrust washers are removed from behind the side gears or else the rear end will be a spool.
As for installing this it took me about three hours and there are some tricks like not upsetting the bearing and nut cap on the one side of the carrier and you do need to have a dial indicator with mag base stand to be sure of the backlash. As for cleaning it all I did not do this but I did pressure wash the diff and axle housing before I took it apart. Keeping it very clean is super important or you will spend three days cleaning everything to be sure that it is not contaminated with any dust or dirt.

After re-assembly with right stuff gasket maker and 50 miles I parked the 4Runner on the driveway with some slope and was able to replace the lubricant in the rear axle with 2 quarts of 85w140 Royal Purple gear oil. I did run the rear end with some 140 Wt straight gear oil for about 50 miles and did some initial tight turns in parking lots were some fairly violent unloading of the locker were experienced and this did shear off some metal which I was able to see on the lower drain plug magnet. So I am glad I did that break in run and would recommend it.

 

The hardest part for me was making sure I reinstalled the adjusting nuts correctly. I made marks and then counted exactly how many revolutions it took to remove. For mine it was exactly 11 turns on each side. When reinstalling those last few turns took alot of grunt. I also went side to side. 3 turns one side, then 3 on the other. I really stressed out about making sure I kept track of the number if turns I made. Make sure and mark the caps so you don’t mix them up. Remove the adjusting nuts and precisely count the number of revolutions it takes to remove. Needed a little heat to get it apart. Remove these locking tabs and toss them. They aren’t reusable and you’ll red loctite them in upon reassemble. You can see how much bigger the pins are on the Spartan versus the Lockrite. Assemble the parts accordingly(YouTube was huge help). Final step is removing the little pins that keep it together until you’re done putting it all back together. This is how it should look upon completion. Reinstall the ring gear using RED Loctite. Wrestle that chunk back in, seal with a FIPG. I used Permatex. Slide your axles back in, reconnect the brake lines, fill with gear oil, and take it on a nice, gentle break in drive.

 

Sweet, the Spartan for the 4 cylinder differential comes with new side gears, with tooth profiles that match. No herky-jerky drive line backlash for you. Although I have figured out how to avoid the herky-jerky, I still get the occasional bind and bang release.

 

No binding per say, just the tire chirping when making tight turns. I’ve learned to speed up when coming up to a turn, then push in the clutch to let unlock. You can hear it ratchet around turns. Recently switched to Redline Heavy Shockproof gear oil. Really helps quiet it down. Has the film strength of 250 wt.oil but flows like 90 wt. iirc

 

Thanks to both of you for such great info. My youngest boy and I went shooting Wednesday, we had such a great time and my runner did really well with all the new stuff, tires, rims and locking hubs. I’m really happy with all the work put in. Kinda questioning if I need a locker.

I called our local driveline shop, he quoted me $385 per drive shaft, R&R U joints & balance. $400 possibly more to install the locker in the rear.

I haven’t done ujoints since I traded my K10 for this 4Runner. Does that seem kinda high $800 for the front and rear drive shaft. Nothing really special on our trucks ?

 

The Spartan for the V6 differential re-uses the Toyota side gears with the thrust washers removed so enough room is provided to allow the hubs to jump across the ends of the gear teeth to allow for it to unlock. Thus unfortunately the herky jerky is apparent when I forget to pay attention. So it looks a bit different from the pictures above. The one advantage I can see is that the V6 version has is that it has a crossed 4 pin X that is forged (which the four spiders spin on) and that doubles the number of surfaces that the X-cross pin and carrier use to push apart the Spartan's hubs when drive torque locks up the axles. Where as the 4 Cylinder one does require removing the ring gear from the carrier to install the hubs inside the carier but it has but only a single pin/shaft (that had only a pair of spider gears on it) that push the hubs apart. So abit more potential for wear and tare on a single pin that is not a cross like the V6 diff has. The Spartan hubs and replacement side gears do look really nice in the 4 cylinder diff though. I can see how the backlash should be less with the 4 cylinder version depicted above. The other nice thing about the V6 diff however, is that the carrier can be separated without the ring gear being removed and that makes the installation very easy for removing the X-cross pin, spider gears and thrust washers that are behind the side gears and spiders. I should have snapped some pics while I had it all apart. I managed to remove the ring gear side bearing cap and spanner nut adjuster with bearing race all together and made sure to keep them together. Doing this made putting it back together really easy. The trick I used to bring the backlash into specification was to knock the spanner nuts around with a flat punch and hammer while the differentials casting and mounting flange was gripped in my bench vice. There is a bit of an interaction between the bearing cap the bearing raceway and the spanner nut all of which has to be understood in order to adjust this backlash correctly. Because once the bearing cap-screws are torqued to specification it can make adjusting the spanner nut very difficult. The keepers which lock the spanner nuts from rotating are important as the diff gets quite warm when all that "torque and horsepower" is sent through this assembly. The thrust loads from the ring gear and pinion can push apart and rotate the race and spanner nut if those keepers are not in place. The assembly is not the same thing at room temperature and then at operating temperature. The red Loctite on the ring gear bolts and the carrier bolts on the V6 are a very important addition to doing this job right as well as a decent torque wrench to set all the fasteners to specification! When I removed my third member from the axle housing it had 240,000 miles on it and everything looked as perfect as the day it had been assembled in Japan. Torquing the bearing caps and the carrier bolts as well as the ring gear bolts on the 4 cylinder diff is really important. Air or electric impact guns are fine to pull it apart but are not advised for re-assembly at all. So be aware of the YouTubers who do not obey this rule!

 

If anyone is thinking of doing this at home you need to mark the caps and the adjusting nuts, if you want the carrier to go back to its original position. You also need to count the turns of the adjusting nuts and mark the hole the lock tab goes into. I used a center punch like Best Gen but you could use paint if you get it clean enough.

The adjusting nut sets the backlash and bearing preload. Taper roller bearings must have the proper preload or they will start to spall and ultimately fail. When you disassemble the carrier and inspect the bearings and do not find any spalling on the rollers or races you can assume the preload is correct. If you have to install a new bearing or bearings you will have to check and set the bearing preload.

Per the FSM (para 10 below) when you need to adjust the backlash or preload you first torque the bearing cap bolts, this squares up the outer race of the bearing and the adjusting nut in the bearing bore. Then you loosen the cap bolts to finger tight and then turn the adjusting nuts to set the backlash or preload. I did not have to replace the bearings, so when I reassembled the carrier I left the cap bolts loose and installed the adjusting nuts to where it was 2 holes from my marked position. I torqued the cap bolts and then loosened them and adjusted the nuts to the marked position. I found my backlash was too large, so I tightened the nut 1 hole on one side and loosened the other side 1 hole, this changed the backlash but kept the preload the same. I then torqued the cap bolts and it was ready to reinstall.

 

Bthp,
Are all of the u joints on both the front and rear driveshafts worn out?

 

No, just thinking after 5 years an ounce of prevention is worth a pound of cure. I don’t know how old they are and and I have some pretty decent trips planned before the end of this year. California, Utah, Arizona, Colorado and possibly Houston.

4Runner is running great and that’s one of the last unknowns. Might as well get them done.

 

Personally I am a strong believer, if it works don’t fix it.

If you can twist and shake the driveshaft and not see or feel any play in the U joint, you don’t see anything that looks like rust coming out of the grease seals and you have greased and the U joints accept the grease, I would say there is nothing wrong with them. If you find any defects, I would only replace the one that is bad.

Grease and inspect them regularly and you will get another 100k miles out of them.

 

Mmmmm ya know the original frame mounted fuel filter made it 180,000 miles. I’m glad that it failed in town cause that’d been a bitch to do on the side of the road. Not taking the chance with so many miles planned ahead.

Generally I agree with you, if it ain’t broke don’t fix it. I had a rear drive shaft go out in my K10 on a cross country trip, talk about luck, I took it out and ran on the front to the next exit in whatever state we were in and damned if there wasn’t a driveline shop like a mile away.

Did the original come with grease fittings ?

I just checked, mine all have grease fitting and they’ve never been touched from what I can tell. I’m betting they’re the origina that came with the truck. If they are that’s pretty damn good the grease fitting are big square buggers, not like the little zerk fitting I’m used to seeing.

 

For me, if it works don’t fix it, does not apply to scheduled maintenance items. Ignore the scheduled maintenance items at you own risk!

Toyota recommends greasing the driveshafts every 7500 miles, on dusty roads. The OEM grease fittings should just be a normal zerk fitting. You might want to grease the u joints every time you change the oil.

I couldn’t find a fuel filter change interval in the FSM but the Haynes manual recommends a filter change at 30k miles. That seems a bit excessive, I think 60k is more realistic, at least for me.

Make sure the shop that is replacing your u joints understands there are 8 different thicknesses of the bearing snap rings. They set the axial play of the spider when it and the bearings are pressed into the yoke.

 

I get it man, no need to be condescending. I’ve only been retired for a year. Before that kids, and life were happening not everyone has time to handle all the needs of a multiple vehicles whilst dealing with the goings on of day to day life.

I’ve been dealing with one thing at a time the best I can having the time to do so now. Since I traded for this truck there’s really no way to know what’s been done and what’s not. I’ve knocked out quite a bit and most of that that’s been replaced (Original parts coming out @ 170,000 miles) made it way over any of my American Made cars I’ve owned.

I’ll post a few pics in the morning, you’ll see these are probably original. At the very least I’ll need to clean all the zerks, before attempting to grease them. I’m going to order the Matsuba, not sure on the spelling there u joints, replace then take the shafts down and have them balanced. After I’ll keep up with an every other oil change greasing.

Thanks for the info I’m aware of the different clips.

 

Sorry, I was not trying to be condescending. Just trying to offer suggestions.

 

My bad, maybe I just took it wrong. I do appreciate all that you share JTM it’s always very helpful .

 

Well, think that’s an original U joint.

looks like I have a few other issues too. Looks like a have a small leak at the 02 sensor. One at a flange and a few pinholes in the muffler. Maybe original muffler, if not it’s been on there for awhile..LOL.

 

As for the Toyota OEM u-joints my only new vehicle was an 1982 4X4 long bed pickup that is still knocking around in Bishop, CA. I had 250K miles on the original drivetrain when I gave the truck to my sister and the key was giving the zerks about 2 to 3 squirts of grease avery 2,500 miles. If the four wheel drive had been hardly used in that interim I would skip to 5,000 miles for the front drive shafts double-cardiane and front u-joint. It is great to realize that my 91 4Runner has the very same joints and double-cardian and that it is all in good order now at 240K miles.

But as for the Spartan that I had installed a few months ago I have replaced it with a Yukon Grizzly carrier and am not seeing anything like the backlash I had with the V6 Spartan that uses the side gears to mesh with the hubs. Unfortunately this is a lot more money and is more than double the cost of the Spartan. I reused my ring gear but purchased new carrier bearings to press onto the Grizzly so a little more money for those bearings as well.

 

Thank you atgparker, I have the joints now but I’ve decided not to replace them. Going to see how far they go as is. I read your new post on the new locker, as usual very informative and glad to hear it’s an improvement over the Spartan, and it’s certainly helps guys like me on making the best choice when I get to that. For now I’m totally satisfied with my 4Runner, she’s running stronger than ever, gas mileage is decent and everything continues to work, I luv my Toyota . Right now I’m working on Comms, so she’s getting both CB and a HAM mobile radio and I’m studying to upgrade my license from tech. I’ll keep lurking enjoying the info posted.