I found a deal on a Dana 30 out of an 89 xj that has vaccum disconnect and 1 piece axle, also has 373 gearing which will match my rear in my blazer. Dude only wants a couple hundred for it. What r your thoughts? Sound like a deal? Pros and cons about the vaccum disconnect and 1 piece axle shaft would be cool.

 

I just bought a front and rear yesterday for 600 out of a 90 yj and I think I'm going to like them my gears are 4.10 and I have to rebuild the front . I'm buying the cable locker for the front I don't care for the vacuum set up .

 

dana 30s are jeep people as 10bolts are to chevy people. all the hardcore guys hate them and weekend wheelers say they are ok. all depends on what size tires you are running and how bad you are gonna beat on it

this is what you have in the rear

GM CORPORATE 10-BOLT
The GM 10-bolt is named for the number of bolts on the cover; ring gear diameter is 7 1/2 inches. Variations of this can be found in the rear of GM S-trucks and some Isuzus, and in the front of S-trucks.

and heres the dana30
DANA 30
The Model 30, with a 7 1/8-inch-diameter ring gear, was the standard front differential in some 1972-75 CJ-5s and all 1975-and-later CJ-5s and CJ-7s. It is still used in the front of Cherokees and Comanches, and will probably appear in the front of the Grand Cherokee.



so they are pretty equal i guess in strength wise. i wish the s10s would have came with 30s from the factory

 

I was hoping.for.some.more.info.on the other specs;

 

The best option for a Dana 30 is to swap it out for a Dana 44.

And not all 10 bolts are created equal. I have a 10 bolt that has 8.625 gears in it.

 

Dana 30 is fine for what it is. Up to about 34s with light trails and it'll be ok. If you plan on putting bigger tires, rough riding it, or dropping a v8 in you blazer don't waste your time. If its got a 1 piece axle swapped in then the vac stuff isn't there anymore. Common upgrade but unless its had locking hubs added the front end will always be spinning and kill gas mileage. The xj used radius arms so if you are using leaf springs all the brackets will have to be cut off and swapped to leafs.

Last pair of danas I picked up I gave $150 for the front 30 and rear 35. I'd suggest hooking up with a local 4x4 group then looking. Some jeep guy is always getting rid of a 30 for something better. I gave $200 for a set of 44s from a buddy I met like that who was going to 60s.

 

Can you explain the I piece axle part a bit more? What does a locker have to do with how it responds if its not even in 4wheel drive? As you can tell, I'm new to all this kind of stuff. I'm one hell of a fabricator but when it comes to the other 4x stuff I'm still learning. I know that the Dana 30 isn't much stronger than the stock setup but the way I see it is, it has the same gearing that I currently have, which will allow me to use it without regearing yet. It will also allow Mr to get rid of so many of the moving components I keep breaking. Like folding a arms in half, balljoints etc. Plus I can't seem to keep my camber right as it is now with the ifs. That won't be a problem with the Dana 30. Why would the vacuum disconnect be worthless now with the one piece axle shaft?

 

the 2 piece axle shaft has splines on each end. u put transfer case in 4x it triggers vacuum to a housing on the dana 30 to engage a drive flange. this flange slips over the splines on both parts basically connecting it so it can output to the drive tire/ 4wheel drive. Reason for this is so the wheels are free spinning instead of driving the ring and pinion and transferring that to the driveshaft and spinning the front output of tcase.

So now by eliminating the vacuum engage and drive flange and going 1 piece axle shaft. this eventually has your axle locked in ready to go. constantly engaged spinning everything above. this does add rotational mass, and can effect mpg and wear and tear since it isnt doing anything but free spinning. u change this by adding locking hubs so u can disengage the axle so its again only free spinning the wheels.

our blazers are heavier and have more power then a jeep. youll find the weakness of a 30 quicker then a jeep will. just a guess, if your bending a-arms, u like that skinny pedal...lol my opinion, a stock 30 is not worth a "couple hundred".

 

to sum it up its a clustercrap design and you dont want it lol. i dont know whats worse, that two piece axle set up or those vacuum outer hubs that the new fords put on their trucks. wtf were they thinking!

ive worked on a few fullsize dodges where that little gear that is supposed to slide to lock those two axles together gets one little tiny burr on it and it wont slide.

i wonder if you can find some old bronco or scout axles to use those should be pretty beefy.

im running fullsized 10 bolts and 33s on my s10 and they scare me sometimes. id say im just about on the limit id be afraid to go any bigger

 

HAHA! that works too!