Brake/Dana swap question.

I have a 1964 CJ5 that I'm currently refurbishing. It's an F-head and has a T-90. It also has a D25 with a 5.38 ratio. I've read around the board and think I have a decent plan but I want to make sure that this can work.

I want better brakes and have found a couple of 4.56 donor axles from a 72 cj5. The front is a D30 with disc and the back D44 has 11" drums. They each have a broken axle and of course the back is not offset like my current D44. My plan is as follows:

Swap in the the D30.
Swap the brakes and ring and pinion on the D44.
Put in a dual MC retrofit from Herm.

Now the questions:
Is a '72 D30 an essentially bolt on conversion?
Is the Ring and pinion or even the whole carrier swappable between D44's?
Can a 134 handle 31 or 33 inch tires with a 4.56 ratio?
Or am I better off finding a 5.38 for the D30?

What do you guys think?

EDIT: I was wrong my CJ has 4.27 gears.

 

do an 11" brake conversion on all four corners and leave it at that.
you'll be fine.

 

I agree with Jpflat. If you're just looking for brakes, this is the wrong route. The discs in front will open up a new can of worms using your original brake system. As an owner of a 134 powered jeep with 33's, I wouldn't want gears any higher (numerically lower) than 5.38's. They're just low enough now to keep it feeling halfway peppy on take off. Given, mine is a flat head, but I still don't feel you would be happy with the 4.56's.

On the other hand, if you're looking for strength, and are willing to do the work, the 30 front will help in a lot of ways. I'm currently looking at performing the same swap, but I will be throwing 5.38 gears into the donor axle. You'll get a better turning radius, and less maintenance required from the swap, plus you open up a whole new world of differential options.

If you really want to go this route, why not find a D20, so you can swap in both front and rear axles? The rear 44 you have is a much more durable unit than the offset 44 you're currently using.

I guess it all depends on what you want to do with your jeep in the future.

Just my two cents.

 

I would just do an 11 inch brake conversion my self
the d30 will require new steering linkage
the d44 will need the gears set up
it would be easier and cheaper to keep your axles and go with break upgrades, and if set on disc, Herm makes a disc setup for your front axle

 

The D30 will bolt in for the most part. Tie rods, brake hoses and drive shaft/u-joints may require changes.

The D44 ring gears will go in the old axle but you must use the newer yoke with the newer pinion and the old carrier to match the older axle shafts.
You also can't exchange the spider gears between the carriers since they changed bearing sizes when they went from 19 to 30 splines.

 

Thanks for the input guys!

As for this Jeeps uses it's going to be stored up at my backwoods camp for berry picking, trail expeditions and plowing the drive. Only highway use is very rural and usually without seeing more than one or two cars. I want the better brakes because I hate mud snow water brake fade.

I hadn't thought about dropping a D20 in there and using both axles. I think that's the most practical upgrade route because the Replacement D44 has a Detroit locker in it -- something I'd like very much for plowing and using both axles together without swapping gears wouldn't involve any pinion setup.

Anyone know if the overall length of a T90/D20 is the same as T90/D18?
Will I need a Driveshaft from a '72 or will my '64 work?


Edit: I see I need a Novak #90-20 adapter to put it behind the T90 (http://www.novak-adapt.com/catalog/kit_90-20.htm)

 

Should be the same length

 

That's just a T-86 rear bearing retainer. I'd put an ad in the Classifieds section and see if you can buy one used before spending that money.

The length will be close but be aware the 20 has the rear output in line with the output of the transmission, not in line with the front output (i.e. lower down) like the 18. Certainly not insurmountable but something to be aware of, i.e. U-joint angles, if running a significant amount of lift. Just be aware also in stock form the 20 has a 2.03-1 low range vs. the most common 2.46-1 low range of the 18. Not trying to dissuade here, sounds like may be a good way to go for you, but things to be aware of.

 

Thanks Nickmill,
I was aware of the ratio difference but not that it was just a T98 rear bearing retainer.

I plan to run 2.5" lift springs -- nothing drastic.

Converting to a center diff in the back won't that make the drive-line angles the same as when it was offset with the D18 and the early D44? Oops! Didn't see that it's vertically different.

 

First of all.... Thanks everybody for your input.

I figured now is the time for major work while I tear it down to the bare frame in my driveway and workshop.

As I was getting ready to pull the radiator I noticed the front axle still has its tag. It was really rusted so this is a flipped image of the back of the tag...

The front was unreadable. Sure looks like my last 3 S/N and it looks like a 47 11 (4.27) underneath. 5.38 is what I thought all f134's came with but I guess I was wrong. Further reading on the board gave me this Service Bulletin Thread. So it looks like my '64 would benefit a little in high range with the 4.56 axles. With 32" tires that should put me right at a 54mph 2600 max speed.

It has become clear to me now, I will pick up a D20 and do the swap -- If the crawl ratio bothers me I can always re-gear the D20 and be back where I started except with improved axles, a locker in back and better brakes.

 

I wouldn't want any less gear than I have now with my 5.38 and 2.5:1 low range. The easily sourced D20 will have a 2:1 low range combined with the 4.56 will mean a motor swap or T98 swap next. I think the 11" brake swap would be easier, cheaper, and much more effective in the end. Use the money to buy a couple of LockRights.