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USA Standard Gear

USA Standard Gear (SL M20-29) Spartan Locker for Model 20 differential with 29 spline axles

    • Based on 1,798 reviews
Condition: New
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Availability: Only 1 left in stock, order soon!
Fulfilled by Amazon
Arrives Monday, Nov 25
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Style: Model 20 Differential 29 Spline Count (SL M20-29)


Features

  • Easy, drop-in installation
  • Made from 9310 steel
  • Heat treated and precision cut teeth
  • Backed by 1 year
  • Fits AMC Model 20 Differential - 29 Spline Axles

Description

The Spartan Locker, by USA Standard Gear, provides reliable traction at a low cost. The Spartan locker's design does not use the thrust washers and has a revolutionary spring and pin design that makes installation a snap!


Is Discontinued By Manufacturer ‏ : ‎ No


Item model number ‏ : ‎ SL M20-29


Date First Available ‏ : ‎ February 13, 2012


Manufacturer ‏ : ‎ USA Standard Gear


Country of Origin ‏ : ‎ USA


Best Sellers Rank: #5,666 in Automotive (See Top 100 in Automotive) #4 in Automotive Replacement Differential Assembly Kits


#4 in Automotive Replacement Differential Assembly Kits:


Customer Reviews: 4.6 out of 5 stars 1,798 ratings


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Monday, Nov 25

Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.

To initiate a return, please visit our Returns Center.

View our full returns policy here.

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Similar Products

Top Amazon Reviews

    • Easy to install Can't tell it's installed
Style: Dana 30 Differential 27 Spline Count (SL...
Review Image by Stevo
Review Image by Stevo
Overall it's a cheap locker, it works when in 4wd and you can't tell that it's there. In my short time running this locker I like it and this review will change based on my experiences with it. My reason for buying this is my U Joints in the Dana 30 High Pinion on my 1998 Jeep Cherokee decided to sheer off some teeth from binding and this was roughly the same price as a new set of spider gears so I gave this a shot instead of getting a front selectable locker. After I installed this I noticed my jeep now tracks a lot straighter and doesn't have as much wander on the highway. When driving at low speeds, lock to lock, there is no audible ratcheting noise or popping, if you are familiar with Cherokees or any vehicle that has U-Joints in the front with a 50-50 power split as in the NP231 in a Cherokee when in 4wd and turning on pavement the vehicle wants to hop due to the U-Joints binding, this is natural of 4WD; however, when this locker is in 2wd there is no hoping or rubbing but in 4wd there is noticeable rubbing but no hopping due to both tires spinning at the same rate while turning on the pavement. When climbing over obstacles in either 4H or 4L you can tell the front axle locks up due to the reduced throttle needed when climbing rocks or barriers, in off-camber situations when one tire is either at full droop or on lose material and the other tire has full traction both tires spinning at the same rate as a locker should and unlocks as soon as I engage 2WD. Overall it works off-road and I can't tell it's there in my daily driving. I'd recommend this. Installation - went easy cant have any complaints, in my Cherokee I had to pull the diff cover off, 4 bolts to get the carrier out, took the ring gear off by removing the retaining bolts and smacking the ring gear off with a hammer, you use a small punch to remove the retainer pin of your main cross pin to removed your spider gears, make sure all 4 of your thrust washers are removed, you put the spring into the locky key way thing and push it into the locker and insert a little metal pin that they include, you do that 4 times then you put your splined locker gears teethy things into the carrier then insert the two locker bits that have the metal pins, you pull one metal pin out and allow the locker to engage, once engaged you pull the other three out, then roll the center of the carrier to allow the new cross pin to slide through and put a new retainer pin in that is also included. After you punch the pin in you're done installing the locker just reinstall your ring gear with a soft hammer and put the bolts in torque em to spec reinstall into the pumpkin, bolt up your 4 carrier bolts that go in the pumpkin to retain the carrier then throw some gasket maker on the diff cover bolt that down and fill it with fluid and your done, I'd recommend you jack both tires up and or put em on jack stands so no tires are on the ground, when you turn one tire they both should turn in the same direction indicating the locker is indeed locked, to verify proper clearance and that you wont blow up your locker have a buddy bear hug one of your tires and spin the other if she make clicky ratchet esk noises you're good she'll unlock when you turn in 2wd and when you are in 4wd sending power to the front diff she'll lock up. To be noted I am running 8in lift, 35's, long arms, 1 - ton steering, and during the installation of this locker, I replaced my U-Joints, hub bearing, brake pads, and the spider gears due to installing of the locker so my experience may be influenced by the new surrounding parts. ... show more
Reviewed in the United States on April 13, 2022 by Stevo
    • NIce auto locker but some caveats
Style: Dana 30 Differential 27 Spline Count (SL...
This is a very nice locker. it works very well and installs easily with hand tools and no special tools, knowledge or equipment. (you just need a torque wrench, sockets a punch for the roll pin) Offroad this thing is amazing and will pull your jeep over things that were impossible before. However on-road this is VERY sensitive to tire pressure. Make sure you rotate your tires often and monitor tire pressure frequently. even 1-2 PSI is enough for it to act squirrely. This is especially noticeable for the first 1000 miles. During break in even in 2wd with the locker in in a front differential, It can lock up and make the jeep hard to handle. After it gets worn in - it works like a dream but if you put it in right before winter you will struggle. During break in the unlocks are LOUD -almost like a bang. You will get looks in parking lots where people think you broke something. The steering is much tighter in 4wd then before you put this locker in and it will not turn as tightly in 4wd. Offroad in 4lo with this in the front dana 30 you will have to make more multi point turns (or get a terra 2w low kit for your np231 so you can shift in and out of 2w/4w low on the fly to get the front to unlock) The TJ i put this in didn't work right until i ran it through a couple tanks of gas and flat towed it at 65 for about 650 miles - then it was good to go. In the YJ i put this in it wasn't "right" with the world until just after 1000 miles This does have some negative driving characteristics in 4wd as well. If it's icy you need to be very careful - if you have this in the front axle it will understeer and the locker will not always differentiate because it needs that friction with the road to do so. you will find yourself putting more and more wheel into a turn and then when it finally unlocks it will get squirrely. It will also understeer and is much more likely to loose lateral control in the ice. If you put one of these In the rear it will torque steer (pushing you in a straight line) for as long as you are on the gas. If you don't watch it closely you WILL do unintentional lane changes or donuts when its icy out on the road. Do not just toss the keys to your buddy who doesn't know how to drive an auto locker in in a light vehicle when its shitty out. It will take some time to learn to drive it, you drive allot with your foot - you learn to let off around curves, lane changes etc. Make sure to give yourself some time to adjust to how to drive one of these on the road. Spend some parking lot and back road time with it when its crappy out until you get used to it. When shifting out of 4wd the jeep will have a tendency to not unlock the front axle. If you let it roll with the trans in neutral and turn the wheel back and forth a bit it helps. This gets much much better after you break it it (that first 1000 or so) Finally if you didn't pay attention to the tire size limits - you are much more likely to break axle shafts with larger tires with one of these. Make sure you know out to pound out a u-joint or pull and inner CV . I didn't start breaking things until i went over 33s then it was quite often until i went to 4340 chromoly shafts. The inners are what tend to break on stock shafts and the CV cups blow up on the ZJ shafts. basically take your time, learn to drive it, keep in mind of the limitations and dont judge it until you have that first 1000 or so on it and enjoy the massive off-road advantages ... show more
Reviewed in the United States on January 6, 2022 by Chris
    • Locked 2 Yjs, xj and a TJ....
Style: Dana 30 Differential 27 Spline Count (SL...
Very good bang for the buck.... A little loud on disengagement... Soft locker versions are available and just as effective at a hundred bucks more... Worth it for jeep pilots looking for more capable rig
Reviewed in the United States on January 18, 2023 by Misterhappytrees
    • Jeep would climba a tree if it could get a grip
Style: Dana 30 Differential 27 Spline Count (SL...
Makes "4wd" with open differential a true 4wd. All wheels pull instead of the one that has the least traction just spinning.
Reviewed in the United States on January 13, 2023 by Purple armadillo
    • 09 f150
Style: Ford 8.8 Differential 31 Spline Count (S...
Installed in rear 8.8" '09 f-150. Hardly know it's there 98% of the time. It clicks when you roll through sharp turns in parking lots and such. Inside wheel will chirp if you hit the gas hard pulling into traffic. Daily drive, and dont have any issues with it.
Reviewed in the United States on December 12, 2022 by Jon Sapundjieff
    • Great product
Style: Ford 8.8 Differential 31 Spline Count (S...
The meterials we're great install instructions we're great even a beginner can do it . Great product for the price. Customer service was on point . Will definitely do business with them again .
Reviewed in the United States on December 19, 2022 by jeremy douglas
    • Locker
Style: Dana 30 Differential 27 Spline Count (SL...
Good price but not so easy to install
Reviewed in the United States on January 4, 2023 by David Todd
    • Perfect fit
Style: Dana 30 Differential 27 Spline Count (SL...
Priced just right easy to install, and actually works excellent for what I use it for, my 04 Jeep Wrangler does it’s job and would definitely recommend to anyone who has a jeep
Reviewed in the United States on December 17, 2022 by Christopher Banks

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