D30 - Long shaft or cable to replace vac. disconnect ??????

Hi everyone - I did search, but got lost in the many pages.

Looking for help again. My son just picked up a Dana 30 front axle for his 1988 cherokee. Both axles are vacumn disconnect. He bought the axle becuase it's been set up with 4.56 gears. His 5 speed with the factory 3.07's and 31" tires is a dog. We already have a rear axle ready to go in.

My question - when we picked up the axle the guy also gave us a cable set up to replace the vacumn disconnect and/or a long axle. Neither has been put on this axle.

We have a basic understanding of the vacumn disconnect, but not sure to just use that, switch it over to a cable disconnect or look into installing the long shaft.

I saw a couple of explainations on installing the cable lock out, but was wondering if installing the long shaft can be done by a back yard mech in his garage.

According to the guy we got the axle from the gears were set up professionally, with new seals and bearings about 12,000 miles ago.

What would you suggest and has anyone done a write up on one or the other with detailed instructions?

Thanks as aways everyone here is a wealth of good information

If your gonna wheel it hard go with the 2 piece shaft and replace both sides with the 297x style inner/outers.

If it will see mostly street and mild wheelin I would stay with the disco and there are pros and cons of the cable vs vacuum set up.

Both have some reliability issues.

The disco housings are stronger than the non-disco housings due the cast section at the disconnect.

guess I'm confused. I thought it would be better to have the long axle for strength, than the two piece axle.

Maybe I don't understand. It seems people go to the cable to eliminate the weaker vacumn.

Then it seemed that to eliminate the vacumn and the two piece axle with a one piece would be stonger.

If we put in the long axle, I'm assuming that when you put the transfer case in 4-wheel the front axle is automaticly locked in. Or is the vacumn/cable actually locking in the axle?

Sorry for being stupid :doh: just don't understand.

Thanks

I have gone over this in my mind and a bit on here as well. I too have the stock d30 with vac disco. this winter it crapped out on me a couple of time for different reasons, and as such I purchased a Posi-lok from a member. I have not installed it yet but here is my reasoning for getting it.
I looked into a solid axle and yes it is quite possible for this to be installed by the backyard mechanic and there are several if not more write ups on here.
I chose to keep the two piece axle for manuverability. With the cable set up you can theoreticly use your transfer case and axle independent.
I see the benefit down the line if and when I put a locker in the front I can unlock the right side of the axle and increse my turning radius, manuver. I have simplified A bit but I guess I just wanted to be able to control what is going on upfront in a more straight forward manner... I do dislike vac.

i also have a disco axle. i'm switching mine to cable for the fact that my truck doesn't have vac. also, i don't want to run a auto locker in the front becuae it's still my DD and a full locked vehicle imo suck in winter. so i'll weld my front gears. that way when i want to i can disco my rt axle from left and still have one tire to steer, and 3 tires to grab the snow. also, it will help with turning tight. but, for the same reason, if i want/need more traction, i've got it.

The disco axle housing is stronger than the non-disco housing becuase the pass side ula mount is cast, not welded. i think different people have different views on the the 2 peice axle vs. 1 long shaft. just my .02

boomer1 said:

guess I'm confused. I thought it would be better to have the long axle for strength, than the two piece axle.

Maybe I don't understand. It seems people go to the cable to eliminate the weaker vacumn.

Then it seemed that to eliminate the vacumn and the two piece axle with a one piece would be stonger.

If we put in the long axle, I'm assuming that when you put the transfer case in 4-wheel the front axle is automaticly locked in. Or is the vacumn/cable actually locking in the axle?

Sorry for being stupid :doh: just don't understand.

Thanks

Click to expand...

OK I wasn't clear with my explanation, you now have a 3 peice shaft on the pass. side(2 inner shafts and one outer shaft). It will be stronger to go to the 2 piece shaft like most all 91+ XJ's have and better yet to go with 96+ inner/outer shafts with the 297x u-joints.

The cable actuater is, in my opinion, more reliable than the vacuum shift. If it is set up right.

If you go with the long axle(or 2 piece) you will not need either the cable or the vacuum and is much stronger and more reliable.

I hope this helps

I have had both. With the posi-lock/disc, a shifting collar engages the intermediate axle with the passenger inner axle to engage 4x4. The disco is nice, because when disengaged only the spiders spin, and the front drive-shaft doesn’t. This is better for mileage and vibrations etc...

I finally broke the intermediate shaft, and decided to do the long shaft.

boomer1 said:

guess I'm confused. I thought it would be better to have the long axle for strength, than the two piece axle.

Maybe I don't understand. It seems people go to the cable to eliminate the weaker vacumn.

Then it seemed that to eliminate the vacumn and the two piece axle with a one piece would be stonger.

If we put in the long axle, I'm assuming that when you put the transfer case in 4-wheel the front axle is automaticly locked in. Or is the vacumn/cable actually locking in the axle?

Sorry for being stupid :doh: just don't understand.

Thanks

Click to expand...

The two piece axle is not a problem. I have never seen one break at the junction. The problem is that most are the smaller joint types. I ran a two piece from another type of jeep that had the 297 joints and never had much of a problem, and none related to the disco area. Sorry I can't remember the source of the heavy 2 piece axles.

Having said that, if you are running a quicklok or the equivelent, the disco really does not buy you much off road. One wheel seems to always be driving and a 3 wheel drive is almost a hard to turn as a 4 wheel drive.

I had a posi-lock cable and put it on there and adjusted it a couple times and never could get it quite right. So i got lookin around and i found hose clamp. It was small enough to fit in houseing and not rub slide collar over put clamp to hold it tightened it and havent had a prob.