D30 Non-Disco Shafts in Disco D30

My sons '87 XJ has the disco D30. He's having problems with the vaccum system. He doesn't want to spend the $$ on a posi-lock. I've heard of kits to replace the two-piece axle shaft with a single shaft. My question...can a non-disco shaft be used in place of a disco shaft? What about a complete front axle swap with a junk yard non-disco D30 (expensive?). I've search...and found that it seems a seal is required for the axle shaft swap (at the differental side?)...that seems easy enough. But is that's all that's involved?

I'm wide open for suggestions. As always, thanks in advance.

Flyfisher said:

My sons '87 XJ has the disco D30. He's having problems with the vaccum system. He doesn't want to spend the $$ on a posi-lock. I've heard of kits to replace the two-piece axle shaft with a single shaft. My question...can a non-disco shaft be used in place of a disco shaft?

Click to expand...

That's what the kit allows you to do, run a single shaft. You'll need at least a block off plate. The kit (from Warn) comes with a seal to install inside of where the selector was. I have an 87 HP30 axle in the front of my TJ, with alloy axles. The axles are larger than stock, and can't run the seal. No problems in a year so far.

Now, this may be a good time to upgrade to the newer one-piece shafts with the 297x u-joint. You have the smaller 250x joint. Grab a set off of a 97-up Wrangler or CHerokee if you can.

Ha ha! Man, am I the guy to talk to right now.
Anyway, its really easy.
First you must hunt down a long side shaft, get a '95 or up shaft because it'll be a 297 U joint. If you want get both shafts if you want to spend the extra money, but it won't hurt anything to buy one 297 shaft and have your short shaft be a different U joint. The shaft can be from ANY nondisco Dana 30 it doesnt matter, XJ, YJ, TJ, MJ.

If you've never pulled a shaft before, you're in for a treat getting the hub out of the knuckle. Keep that in mind. A slide hammer will work and lots of Blaster.

Take the differ cover off and drain it. Clean it out around the inner axle tube seal looking in from the diff opening so you can see the inner seal.

Remove EVERYTHING inside and out on the housing that makes the axle a disco. Remove the box, the motor,everything! All the internals.
Gut the damn thing. You'll need to make a plate to cover up the opening.
Seal it up with some silicon.

Now the passenger side should be empty. Look through the tube from the outside and put a light on the inside. You should be able to see through. without obstruction down the center of the tube.

You need to replace the inner axle tube seal. On a NON DISCO, both inner tube seals are the same, same part number. On a DISCO they're different b/c the tube wall thickness is thicker on the disco side (technically a Disco Dana 30 tube is stronger), so the passenger side inner seal is different than the drivers side (short side).

Here's the tricky part... with this solid shaft conversion, this new seal isn't the normal DISCO passenger side inner tube seal called for. It's different:
The one you need is NATIONAL SEAL PART NO. - 471763
This seal should have a smaller opening and fit snugly around the new long solid shaft. It presses in easly. Coat the outside with silicone before pressing it in to make sure it seals completely (reason being: there is not machined lip inside the disco tube for this seal to sit against)

Now, just install the new long shaft. Make sure not to pop your new seal out of place. Bolt her down. Put some new diff fluid in there. and put your cover back on. Amen.
This is a good time to check the other side seal too, it may need changed:
SPICER SEAL PART NO. - 42500
Peace.

there are write ups on how to do the posi lok with out a kit. do a search around, it's cheap and is reliable.
Jeremy

here is another write up for the swap
http://www.stu-offroad.com/axle/yjd30convert/yjconvert-1.htm

if you search YJ forums on jeepsunlimited there is alot of info there as well

Note: There is more than one standard tube Inside Diameter....hopefully yours is the usual one....I have a disco axle that I have never found the right size seal to fit in...without machining or hacking something together....I just bought a whole non-disco axle...BUT you won't know until you open it up.

you say you don't have the money for a posi-loc...

but you're going to replace the axle sahfts?

do the budget posi loc for about $50

Thanks to all for all the replies. The $$ for the posi-lock is only one of the issues....son wants to go non-disco anyway and I was mainly trying to figure out if it is possible. Now that I know it is possible, I'll just have to guard MY non-disco D30 better to make sure the shaft doesn't disappear!

my dad would give me his non disco D30 shaft
:flipoff:

Sorry, I was just rereading my post above,
I forgot to talk about removing the carrier!! Der.
Anyway, to see the inner tube seals the carrier must be pulled out.
Make sure you keep the proper bearing race with the proper bearing!!

I did read about the different thicknesses of the tubes too on the disco side?? Not sure why that is, I kept researching and found lik 4 Part #s I had my local store order all 4 seals, they are like $5 each... I took them ALL home and tried all of them until I found the one that fit. Then retuned the others.

or you could spend 50 cents and shim the fork over with washers

Will the last post actually work and not cause any problems?

Yes.

Does any one have any pics? A little more explanation would be cool.