Dana 30 Swap

So I tried out my 4wd for the first time in the jeep.. and it bucked like crazy. Checking the axles to see if they are the same gearing front an rear.. I bet they are not.

Found a good deal on a set of cj5 dana 30s with 4.10 on both ends. Right now i have a d25 up front.

Will the front just mount right in? Never have done an axle swap.. the brakes are the same as my drums now.. so seems like it should be simple..

 

Check spring perch dimensions to insure they match to your springs, I assume the axle pumpkin offset on these replacements is correct for your Jeep?

 

There are so many other things you should be checking before you get to an axle swap..........obviously gear ratio should be one of them.

Early Narrow track spacing between spring pad center lines on most front and rear axles between 1950 and 1975 should be 28" This would include D-30 front axles between 72-81...........but one should always check.

The early D-30 axle 72-81 will also be 3 " wider overall in hub to hub mounting surface.

 

Depending on year you have a Dana 25 or Dana 27 up front. A Dana 30 is not a complete drop in but can easily be done. You will have to address the tie tod problems, your front driveshaft differences and the spring plates and front shocks and front U-bolts. So long as the Dana 30 is not a widetrack from a cj7 perches and stuff should be fine.

 

oops meant 25.. fixed that.

 

What tie rod problem?

 

For my Dana 27 to Dana 30, both narrow track

On the Dana 27, it was the two piece design. Bell crank to passenger knuckle. Drivers knuckle attached half way up the passenger tie rod.

Dana 30, knuckle to knuckle tierod. Drag link from Bell crank to passenger. I used sleeve and tierod from the Dana 30 and then the Dana 27 tierod. I mix and matched parts to get the right length if I recall.

Depending on engine combo... I had to switch my yoke on the Dana 18, and obtained a driveshaft from the scout.

Engines and transmission get swapped around so it can change length and stuff.

Dont forget to get the castor angle checked too. Shims and leaf spring bolts.

Really is a simple swap and glad I did it.

 

Did you find both front and rear donor axles with 4:10 gears? The intermediate CJ5 should be Dana 30 front with Dana 44 rear. If this is a set, make sure that axle set with 4:10 gears has an offset rear diff. From '72-up, the CJ5 rear was centered, and won't interchange easily if your original is an early offset diff.
I would open up your existing diffs and get tooth counts to know exactly what you have in there, and their overall conditions.
-Donny

 

The tooth count is stamped in to the edge of the ring gear, ie "41 11" is 41/11 = 3.73.

Re the Dana 30, 4.10s were not offered in a CJ until '76 and later, so the rear axle might be a M20 (AMC 20 Corporate) rear axle. All CJs used the M20 as a rear axle from 1976 on. The 20 is centered, the wrong axle pad spacing and unpopular because it is weak, so not much of a prize. Could be a '72-75 centered Dana 44 rear, but it would have to have had a gear change to be 4.10s.

 

Here is the only picture he was able to send.. does it tell us anything?

 

Yes, that is an AMC20 rear axle which will not play well with your transfer case offset. The pumpkin on the 20 is centered and the one on your 44 you have now is offset.

If I were you I'd hold out for a disc brake version of the Dana 30. I bought a wide track to widen my stance but there are narrow track disc brake versions to be had.

I don't know what your existing gearing is but the only front D30's I've ever seen advertised on Craigs all seem to be 3:54 which is rare in the early CJ's

 

So this is a drum brake 30 paired with an AMC Corporate 20 rear axle. You can tell the 20 from the dome-shaped cover. I'd say this is a set from a '76 or '77, since front drum brakes were no longer available after 1977 IIRC. It also says that these are narrow track axles. The two available ratios in '76-77 were 3.54 standard and 4.10 optional.

3.54s are common for Dana 30s because that was the standard ratio starting in 1976, and I think Jeep continued to offer that ratio through the end of the CJ-5. None of the earlier CJs came with 3.54s.

To me, a narrow 4.10 30 is something of a prize, even if it does not have disk brakes. IMO 4.10 is a very good ratio for a Jeep: low enough to be effective on the trail, but fine on the highway without an overdrive. Unfortunately that rear axle is not usable with your transfer case, and it's a cigar butt of an axle anyway. All the value there is in the 4.10 30.

 

Lol... cigar butt! One of the front Dana 30's I looked at came with a free AMC20 rear axle. I asked the guy if he would just sell me the front and he said no, you have to take the rear also.

I was on the fence about buying a Dana 30 disc brake front with the wrong gears vs. buying a Dana 44 disc brake front with the right gears and shortening the tube/axle, welding perches etc. I could never decide which way to go and then a wide track Dana 30 in good shape at a price I thought was fair came up and that made the decision for me.

 

I got a narrow track D30 with disc brakes for free earlier this year. It has 3:73 gears, I have 4:88.
With 3 in college, funds are tight but I may tear it apart this winter. Maybe someday it will find it's way under my Jeep.
The D27 has held up to a lot of abuse over 20+ years though.

 

Look again at the picture, it looks to be an offset M20 from a Q-trac tc. If the front axle has drive flanges instead of locking hubs, that is another indicator of an offset rear. If it is an offset with 4.10s that is an incredible find. Spring perches, bolt them up and drive.

 

If you want to upgarde, you can find a set of dana 44 from a waggy with a quadra trac (rear axle is offset) but it's a 6x5.5 lug pattern.

 

I see what you're seeing, but I think it's an illusion. Check out where the brake line is coming out of the backing plate. For it to be offset in the right direction, the wheel cylinder would be on the bottom.

 

Offset MC20's do exist but I don't think they were CJ axles right? Maybe Waggy.

Here's a pic of one, the offset is pretty extreme and doesn't look like it matches the photo above. I think it's optical illusion.

 

CJ7's had offset m20's with q trac

 

Didn't see the brakeline on my phone. Good catch. I haven't ever had a Q-trac with 4.10 gears either. Still worth getting for the gears alone. I have several 20 rear ends that might actually be sellable with 4.10 gears.