New TJ D30 shafts in an old D30

[holeski]

The MJ has 4wd once more. I swapped out the old 3 piece vacuum disconnect with the newer TJ 2 piece shafts. Benefits of this are faster 4wd engagement, Less parts to break and stronger u-joints.

I pulled the front Dana 30 diff cover and drained the oil. I then pulled the vacuum disconnects and drained this. After pulling the tires, brakes rotors, axles and throwing the dust cover in the trash. It was time to start the real work. The block off kit comes with 3 new oil seals the aluminum block of plate and gasket. The 3 seals are not the same as either the old Dana 30 or the new TJ Dana 30. This is why I went with the kit from Randy’s R&P instead of make it myself. If you order one let them know Holeproof Industries sent you. I first took the seals to NAPA to try and cross-reference them. Only one crossed, but this is the most important one. The one that goes in the pass side of the diff. See there is no seal here in the old 3 piece axle set up since oil need to flow down to where the disconnect is. I pulled the ring gear and carrier and pulled or knocked out all the old seals. There is also a roller bearing in the disconnect housing that should be pulled. The new shaft is thinner in this area so it won’t touch it, so you don’t have to pull it but it makes putting the new seals in easier. One seal (NAPA 11566) went where the outer pass side shaft goes into the disconnect housing and one (NAPA 11343) in the pass side of the diff. Now the 3ed went no where to be found. I put the seals in and bolted everything back together. Filled with gear lube and went wheeling. The only thing I don’t have now the 4wd light witch I think I can hook up some of the old vacuum lines to make it work. This however won’t work on say my newer YJ since the light switch is electric and not vacuum actuated.

 

 

Seal info.

Pass side diff

Kit National 471763

NAPA oil seal 11343

 

 

Outer disconnect housing seal

NAPA oil seal 11566

Looks to be right one from the NAPA seal book.

[pingpong]

When Ihad my disco axle I used a D44 seal in the outer part of the VD housing, and it held up fine ror well over a yr, until I got in the hurry on the trail changing an axle shaft.

 

 

Good info all the same

 

 

Patrick

[Eagle]

Many thanks for the number of the seal for the passenger side of the diff. Did it fit right in, or did you have to do any machining of the opening for the seal to fit?

 

What I don't understand is why there are two other seals. The factory setup for no disconnect is just one seal, at the diff housing. What's with the second seal at the disconnect housing? If an axle with no disconnect housing doesn't need a seal in the middle of the tube, why does having an empty disconnect housing around a one-piece shaft require a seal?

[Krazeeun]

I plan on doing this very soon, what did you do with the vaccuum fittings on the Tcase?

[Cabz]

disconect them from the vac actuator and plug one and put a vac line on the other too , to connect them .

This way your 4w4 indicator light will work

 

Thats what I did with my 88 the 91 may have a diffrent vac setup though

[holeski]

No machining was needed to fit the new seals in the diff. The second seal that fit into the disconnect seems to be a safety or redundant seal, a just in case kind of thing. The third seal I think must be for a different year maybe. Throw them all in there so they only have to make one kit for every year that the seals might have changed.

 

Thanks for the how to on the 4wd light. I was thinking I could do that but haven’t tried it yet.

[holeski]

I capped one of the vacuum lines and looped the other two together and the part time light works like a charm. Now if I only could do that with my 94 YJ that now has a front 44.

[Cabz]

8)