Opinions on a Dana 30 and AMC 20

Looking for some opinions/comments on two complete axles I'm planning on buying. Front is a Dana 30, 3:54 gears, open, w/ disc brakes. Rear is an AMC 20, 3:54 gears, open, drums. Both are narrow track. $125 bucks for everything! Seems like a good deal to me, but what are the negatives (if any) with this set up. I read that some people don't like the AMC 20.

I would be swapping out my Dana 25 front, drums and Dana 44 Lincoln Locker rear (meaning previous owner welded the gears together). So I would be getting rid of that plus gaining disc brakes.

As I recall there may be a master cylinder issue with going to disc??

Thanks in advance. All opinions welcome.

 

Mike, the 30 is fine - no problems, except that it's not a 44. You may not like the 3.54 gears... unless you do a lot of highway driving.

The M20 is ok ... their main problem is their two piece axles. You can buy one piece axles to beef them up. Sometimes the axle tubes spin or bend, but I don't think that's very common. The flanged Dana 44 is preferred, but the M20 with aftermarket axles is probably as good.

 

Yes ...

 

Can I just change the gears out in the Dana 44 to match the Dana 30? I don't know a lot about what's available. I don't think I've heard of a Dana 44 w/ 3.54 gears. This is strickly an off road Jeep, so I'm not concerned w/ highway speed. I'll be running 33" tires max.

timgr, I misread the your highway comment. Will I be unhappy with 3.54s for trails or is it just average?

 

My truck has 3.54s. Even with 28" tall stock size tires, I can drive on the highway at 75 mph easily. My crawl ratio is 21:1 ... good for a farm truck but not really slow enough for rough trails. My truck has 44s front and rear.

The early rear 44s had two piece axles, with a nut on the end - is that what you have? I'd be more inclined to keep the 44's ratio and change the 30.

 

I have a set from a quadratac that is offset it is 3.54

 

These would be from a CJ-7 with an automatic, 76-79.

 

I don't know if I have the two piece or not. I'll probably open everything up tomorrow and take a look. The thing I don't like about my 44 rear is that it's been welded into being a locker, the previous owner told me. Seems like that would be a little unreliable.

So, the AMC 20 is no good to me cause it's a center diff. I could buy the Dana 30 for the front disc brakes, but then I'd have to switch the gears to match the rear. The Dana 44 rear I would eventually switch out to a real locker. I don't know if I'm saving any money or just creating more "project". I could get the Dana 30 from end to end for $70.

 

I don't see an easy route ... though I think the 30 is worth having for $70. The disk brakes are certainly worth that much to someone with an Intermediate.

The 3.54s might be ok with a wide ratio 4-speed (ie T18) and the stock Dana 18, then you'd have 6.32*2.42*3.54 =54:1, which would be fine for most people. Used 3.54 gears would be easy to find at IFSJA or other FSJ sites.

The following offset rear axles are out there:
D44 with 2-piece nutted axles (pre 70ish), D44 with flanged axles (70ish-71)
Ratios: 4.27 and 5.38 with the F134, 3.73 and 4.88 with the V6.
The offset M20 mentioned above, with 3.54 or 4.09s.
The flanged axles are better, but comparatively scarce and in more demand. I'd guess the 5.38 with nutted axles is the most available.

From 72-75, the CJ D30 came with 3.73 or 4.27 gears. These have 11" drum brakes, but the D30 disk brakes can be added by changing everything from the knuckles out. After '76 the ratios change to 3.54 and 4.09. A few were built with standard 11" drums, but almost all were disks after '76.

 

Oh, boy, me and my can-o-worms. That's a lot of good info Tim. I definately don't want to change out the tranny. Based on your info and other stuff I've read, it's probably a '76-'79 Dana 30, maybe later. I guess I'll get it. It's not EXACTLY what I need, but I may not ever come across the the exact, perfect set-up. Gonna have to mix and match something somewhere anyway.

Not sure if I'm going two steps forward and one step back or one forward and two back. R) Thanks.

 

Wouldn't a '42 MB have a D41 rear?

 

IIRC the MB/GPW came with a Dana 23 (?) full-floating rear axle. Not strong enough for a V6, I presumed it had been replaced since Mike in Vista wrote it was a 44. The 2A (and 3A? 3B early 5?) had the 41 - I don't know much about it. That too could be used as a replacement.

 

Yeah, it's a Dana 44 rear. I need to change my Jeep's description. It's actually a '42 tub on a '49 chassis. The 44 and 25 might be the originals.

 

I bought it. Here it is. If nothing else, I can use the skid plate and axle truss on my Dana 25 if this doesn't work out for me. It's got the weaker 5 bolt hubs, which I don't like.
View attachment 8840

 

I have a set of wide tracks on my 1985 cj7. The D30 has a lockrite and 4.10 gears. The AMC20 is open, but has been retro-fitted with one-piece axles and 4.10 gears. So far, I have no problems with the setup.

 

Should be able to change over to the 6 bolt hub.

 

Yep. I read somewhere else that I can switch those hubs out. For now, the Dana 30 is gonna get stuffed in a corner somewhere until I tie up some other loose ends on the Jeep, e-brake, tire rack, oh yeah and road test.

The 30 probably wasn't something I really needed to buy right now, but it was cheap and it was close to my house.