Re gearing

Re gearing


Full Time Jeeper
Cincinnati, Ohio
1985 jeep cj7 360 20 rear and 30 front w/warn lockers 5 speed tranny,

1971 dodge dart built 318
I need 4.56 in an AMC20 and Dana 30. I have what I think are 2.73. A guy that I talked to said that I would need new carriers. Is this true?
For the AMC20 rear end 2.73 is the borderline. Any gear lower (numerically higher) needs a new carrier.
For the Dana 30 you will need a new carrier for any gear above 3.54
So I'm looking at a grand in parts? I wish I could cuss on this forum.
With my setup, what do I need? I am not knowledgeable about this topic. If someone in the know is bored, a parts list with links would make this guy real happy. Want to see the parts and how much they cost! Thanky!
What kind of differentials do you want? Open, limeted slip, automatic lockers, selectable lockers.
Please explain. I should be searching the site, but if you are good on time, learn me!
Open differential is best for street use and worst for off-road. It has the best control. Problem is when you are off road you may spin a tire. Whatever tire is easiest to turn will spin even if the other tire has good traction.

A Locker will lock to make sure both tires turn in unison. This is best for off-road. They are not good for street use though. Lockers are the best way to make sure you always stay moving. You may not move the direction you want but you will stay moving. What I mean by that is it is more likely that the rear tires may break loose on wet or slipery roads and you can fishtail and maybe loose control. Be careful with the skinny pedal on the street if you have a locker.

A Limited Slip is a compromise but they are still better for the street than off-road. They allow a little slippage then try to apply torque to the tire with the best traction. Some Limited slip differentials are better than others.

A Selectable Locker is the best of both worlds. You can have an open differential on the street. But when you are off-road and worried about getting stuck then you can activate the locking differential to make both tires turn in unison. Some selectable lockers are electric (activated with a button). Some are cable activated and you use a small shift lever. This is the best option but it is also the most expensive, $1000 per axle.
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I have lockers now, I would just keep them. Do they need replacing during the re gearing?
I have lockers now, I would just keep them. Do they need replacing during the re gearing?
Are you sure you have lockers (locking differentials) or just Warn Locking hubs?
If you have locking differentials then yes they will need to be replaced when you regear your differentials. When you go to 4.56 gears you need to replace whatever type of differentials you have.
If you are going to be taking the cj offroad, than putting lockers in now when you regear would be the best time as you will already have the diffs. apart. (one bill instead of two $$)
As dave said your warn locking hubs are not lockers, they only conect and disconect the front hubs from the axles.
So I have an open diff now? I am mainly using her in the snow for work, 80% street, 20% off road. Maybe a Limited slip?
I have 35's. Thank you for putting that list together, I appreciate it!
Just to add to Dave's list, setteing up the gears front & rear will run app. $800 at a shop around here.
So I have an open diff now?

Jack up both wheels and turn one by hand, if they turn the same way you have a Limited slip or locker. If they turn in oppsite directions you have a open diff.
In the front you have to lock your hubs first.
I put in true trac in both front and back in my CJ7. If you want to wheel it mild may want to upgrade to one piece axle in the AMC20. Only about $250 on depending on what brand. I also upgraded the Dana 30 axles to 4340 chromoly. And if you do upgrade the frount get the big spline 30, same price. I did the upgrade in front and didn't think about the 30 spline untill I was done, stuipd I know. Just know if you upgrade to the 30 spline you'll have to get the carrier to match the 30 spline I think didn't do upgrade not sure. May have to get hubs upgraded up to 30 spline not sure. But if not wheeling much I would just get the one piece in the 20. Hell for 250 more one less thing to worry about. I like they helped me out alot about what I wanted to do and what I Was using it for. If mostly street go limitedslip truetrac best in my opinion no clutchs to wear out. Will have to call 4wd don't have the truetrac in catalog or online for the AMC20 they order straight from factory to you. Sorry so long just tring to think of all the things I looked at went upgrading. If I think of any more will post.:):grinjeep:
Oh $800 is what I paid to get my gears setup axles put in and everything. With diff. setup. close is not good enough. If putting $1200 for back axle or $2000 for both, I would just pay someone to do it. Easier and cheaper in long run if set up wrong gears wont last long. Lockers like was said before lockers are the best to go but cost more. No one knows what you want or what to spend but you. No cables or extra air lines and compressor to buy, With Limited slip a lot cheaper but less proformance.:)
Going Limited slip and 4.56. Guy quoted 1450 for diff and Yukon gears installed.
Going Limited slip and 4.56. Guy quoted 1450 for diff and Yukon gears installed.
For both axles? If so that's cheaper than the quote I gave you for parts alone.
Also what Limited slip? They aren't created equal.

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