'Thick cut ' gears

can someone explain the how and why difference between what I'm guessing would be a 'standard -cut' gear? I have a 2010 JK Sport w/ factory 3.73's :thinking:

You would get thick cut gears if you don't replace your carrier. There's a carrier for 3.73 and lower gears (d44) and then there's a different carrier for 4.10 and higher gears, but you can get thick cut gears to run the smaller carrier.

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Are you talking about the D44 that actually has a thicker ring gear compared to older D44 axles?


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CerOf said:

Are you talking about the D44 that actually has a thicker ring gear compared to older D44 axles?


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No, I don't believe that's what he's saying. Paul was saying- most axles have a different carrier for either higher gears, or lower gears, with the cutoff mostly being around 411. This happens because the pinion gear gets smaller and smaller the numerically higher the gears get, and when the pinion gets smaller, it in turn moves away from the ring gear ( which is bolted to the carrier). There are 3 ways to make this work.

1- a new carrier that moves the mounting surface of the ring gear closer to the pinion

2- a "thick cut" ring gear

3- a ring gear spacer or shim ( I've seen these used, but wouldn't personally recommend it if avoidable. If you've bought the wrong gears or carrier though, and need to make them work, this can be the option for you.)


My ride- 2001 power wheel, 11" plastic tires, upgraded battery, boat sides, custom bumpers, tow hooks, new paint.

thanks for the info guys it makes sense now , heres the story; I just put 35's on my '10JK w/3.73's-d30 front, d44 rear, I want to put 4.88's, the shop said they could use the exsisting carriers w/ a thicker cut gear, now my question is this- when I put a locker in the rear in the future, will I have to replace the gear again? I think I can get a locker that will accept the thick cut gear correct? I would like a tru-trac up front and a selectable in the rear, ideally i would do it all at once but i don't see the bank account agreeing with that...

Rayz said:

thanks for the info guys it makes sense now , heres the story; I just put 35's on my '10JK w/3.73's-d30 front, d44 rear, I want to put 4.88's, the shop said they could use the exsisting carriers w/ a thicker cut gear, now my question is this- when I put a locker in the rear in the future, will I have to replace the gear again? I think I can get a locker that will accept the thick cut gear correct? I would like a tru-trac up front and a selectable in the rear, ideally i would do it all at once but i don't see the bank account agreeing with that...

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You should be able get lockers just fine. Just remember that you will want to get a locker for the numerically lower gears. (If you have thick cut gears, AND an offset carrier (for the numerically higher gears) then you will be too close to the pinion and it will not work.

Basically when you order the lockers, if you already have the thick cut gears. Just pretend that you still have the 3:73 gears and they will be compatible with the thick cut 488s.

Ps. Some lockers replace the carrier, and some of the cheaper ones use the stock carrier and just replace the spider gears


My ride- 2001 power wheel, 11" plastic tires, upgraded battery, boat sides, custom bumpers, tow hooks, new paint.

This might be helpful since I emailed ARB with pretty much the same question. I do have a '12 though, don't think it will make a difference.

I have 3.73 gears and an ARB in my rear. I emailed ARB asking if my locker will work if I have 5.13 installed, or if I will need a new locker.

Their response: Stock non Rubicon Jk's all use RD117 (locker part #). All JK gears are thick so they take the high ratio carrier regardless of actual ratio. It will work with 5.13's later on.

Big relief for me.

thanks guys! this forum "rocks!"---haha pardon the pun :thumb: