Gearing

I’m looking to regearing my 64 cj5,
Can I use different models like a newer model Jeep like a jk as long it the right differential like a Dana 30 and 44??

 

The modern axles are nearly a foot longer than your older Jeep.

 

If you are asking about re-gearing as in swapping ring and pinion:

I believe the gear sets in rear JK Dana 44 axles are different from the older Dana 44’s, the axles are certainly different.

The front Dana 30 and front Dana 44’s in JK’s are reverse rotation so those definitely won’t work.

 

No

 

What axles and gears do you have now? If you just want to regear you current axles that would be the simplest and easiest for you or a shop to perform. The closest stock set direct swap to upgrade would be the 27/44 combo with 4.27 gears and 11" brakes from a 70 1/2-71 CJ5/6.

 

Yes and no. D44 Cases (Carriers) will fit in all d44 housings, but the newer ones are 30 spline. They use a different bearing, but WILL work. The axles may not, BUT might with the correct spider gears for your 19 spline axles.

The D30 all use 27 spline axles and spiders. The newer cases will fit. The newer gears will work. When you search for the parts, just punch in Dana 44 and Dana 30. You will get compatible parts. These axles were used by MANY different manufactures in their vehicles.

I know, because I regeared my D30 to 5.38 and built a full float D44 of late 50's vintage with 30 spline inners using new stuff.

Edit.
One more thing, If you buy modern gears for your D44, you will need a new yoke as well, since the pinion gears are no longer 10 spline.

 

I currently have a 27/44 diffs, but I’m building up a 30, but the guy I bought the Jeep from has 5.13 gears in the back and 2.73 gears in the front, so I’m gonna re-gear both to a 4.56 or 4.88, I have an automatic transmission with the stock transfer case

 

TH350? With an automatic I'd go 4.10 or 4.27. Even 3.73 would be ok, and you can likely get used 30 and 44 gears cheap. With an automatic you don't need as deep a crawler gear. It's a different style of two-footed driving that holds with the brakes and advances by more throttle and releasing the brake. Good brakes and a transmission cooler will help you.

 

Yes it is the th350

 

I have a set of almost new 3:73 D30 gears for that axle. I don't recall what the carrier break ratio is on the D30 but I think you'll need a new case if you go 3:73 or lower.

 

I’m gonna put ARB lockers in the front and rear diffs

 

Where are you in California? What kind of off-roading will you be doing? I ask because a selectable locker is an expensive item, and IMO you could go with limited slip in the rear axle and leave the front open until you assess the gear ratio you choose. This would be fine for general off-road use somewhere like California, where the trails are generally dry and the weather seldom is below freezing.

How much experience with Jeeps and off-roading do you have? Do you plan to drive the Jeep to the trailhead? There's no shame in staging your upgrades so you get on the road sooner. Indeed, I'd say it's smart to get on the road and try what you've got now, then assess the direction of your upgrades.

 

I live in Northern California, I want to do like Rubicon and stuff like that or as hard of stuff

 

The JK Dana 44 uses a larger ring gear and a much larger pinion along with a different carrier. The Rubicon and Standard JK44s use different bearings, but the same ring gear and carriers. It is possible to use JK Dana 44 gear sets in the older Dana 44 housing if you use a kit from Jantz Engineering. This gives you a stronger set up with the 8.9 inch diameter JK ring gears, a pinion comparable to a Dana 60, all in your original housing.

Jantz Engineering: Jana K4

Mike