Jeep CJ 79 front dana 30, how does it work ?

[PSJ]

Ok so first of all i am a new guy here and new to jeeps as well. I just got an old 79 cj with a bunch of mods done to it. It's been only a couple of hours of wheeling it and i managed to break it already.

The guy who had it told me the thing has "posi" front and rear. What is this supposed to be exactly ? Limited slip ? auto lock ? or always locked ?
I tried steering while on 4x4 but then i broke the axle shaft on the passenger side up front.

And i thought maybe i should just replace the...

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[Mlorint]

Posi is a limited slip, it shouldn't affect the steering to much. Did the shaft break or the u-joint? what size of tire are you running?

 

[PSJ]

im running 35s and it broke at the u joint, but i have to replace the whole thing since it's pretty much chewed up on both sides of the joint. Kinda makes me wonder if it's juste the shafts that are weak or something ? But as i recall i only used 4x4 on gravel or sand surfaces. I thought that it would be pretty much impossible to break anything that way.

 

[Mlorint]

a friend of mine is running 35s with a dana 30 and is locked and has yet to break a shaft or u-joint. If the u-joints were worn that would make them break easier. those conditions should not have caused any failures, but driving style and vehicle play a big part. What are you running for a engine?

 

[blair_b]

I've got a set of widetrack axles for a cj- D30 front, rebuilt and ready, AMC20 rear with the one piece axle conversion already done, but needs to be regeared to the front. Let me know if you're interested in gaining some stability while you remedy your current situation.

 

[PSJ]

it's got a edelbrock 350 crate engine with a 3 speed turbo tranny, so it's pretty powerful but im pretty sure i never pinned it while in 4x4 since i only used 4 lo. Is it possible for a limited slip to stick and not slip at all ? Because i was turning on a gravel surface in 4 lo and heard a bang coming from the front and it was the shaft that gave way. That's abnormally weak now isn't it ?

 

[Billygoat]

Thats alot of power with 35's for that axle...

May have been pre-stressed by the PO. He may not have treated it with the same respect as you.

 

[mucovich]

those CJ dana 30's are the weakest of the dana 30 family - they came with the tiny u-joints and are low pinion i believe. With that motor and those tires I don't think that axle will survive very long after you fix it.

 

[Root Moose]

Just fix what's broke for now. The PO may have been slack on u-joint maintenance or like someone else said it could have been previously fatigued and due to let go.