RobG

Went out in the dessert this weekend and on the last hill of the day I heard a bad noise when backing down. Got out to check the tires for rubbing and saw this (attachment).

Apperently the Axel popped out of the CV joint near the differntial on the drivers side. I've heard about front axels breaking but didn't expect this. We tried to get it back in but no luck so we limped back to camp with some wire ties and got it towed home.

Any idea ho this happened? Is it common ?? Can it be prevented ??

I searched and only found 1 person that had a similar problem but his popped back in on the trail.

I am running a 4" super lift front Kit with the standard bump stops, no sway bar, and ARB's front and back. This was my first trip after the lift. We were attempting a sandy steep hill with small rocks at moderate speed (30 MPH) with both lockers engaged.

My next planned mod was locking hubs and bump stop moves. I was really wishing I had gotten aroud to the lock hubs before this trip. I question increasing the front travel as it seems this problem would be more likely to happen.

Rick F.

Wow! That looks nasty! Since I don't off road, I couldn't tell you how (un)common that is...

outdoorfever

bump. I have never seen that. maybe you''ll get some more answers.

jimbo74

not uncommon at all

with that much lift and the CV, you are severly maxing out its design of giving a little bit... with no swaybars you get more articulation, however, there again becomes even less room to give..... what happened is that it clearly just overextended

RobG

The Superlift kit maintains the factory CV angles, the front diff. is moved down 4" inches so if I had a problem with anything I expected it to be the front drive shaft. We tried to flex the suspension (even removed the lower bump stop) to get the shaft back in place in the field and no luck it isn't close to going back without dissasembling components

I just don't understand how it escaped with all bumpstops in place and no sign of bent or broken components. Even with the sway bar removed I wouldn't expect the CV to pop out using factory angles and range of motion. My only thoughts are:
- It is a poor design and this is a fairly common problem (hence the SAS)
- The superlift kit does not retain factory range of motion
- The front locker put to much stress on the shaft

Any input is apreciated, I was seriously considering a long arm IFS kit for next year but may switch that to an SAS if it is likely this will happen again.

cabbage

It happens... Was your front ARB engaged? I think its caused by too much stress with the differential locked while turning.

My differential was welded when that happened... but instead of popping out, 2 of the 3 bearings flew out (stress)... I have a differential drop too and the angles are pretty flat, like jimaben said, happens when the CV's are overextended.

Oh, with the diff drop, although our angles are flat, the whole CV is sitting closer to the lower A-Arm. When I change CV's the lower a-arm is usually in the way making it almost impossible to take the outer part out.

jimbo74

it was still flexed out more than stock design specs... and stress loads in real life are a lot differnt than on a test bench.... also with a locker in the front, that has even more propensity to twist and distort things way more than it should.... metal gives, so it is highly possible it just flexed itself out

WATRD

A hyper-extended CV axle, not unusual. I have seen a few of them go in that way. Take a look at the last few photos in a buddy of mine's gallery; http://www.seattleduffields.com/mike...31019-0002.htm

The cause is usually a combination of lift, droop and turning the wheels. It can be "fixed" a couple of ways; remove the lift or limit the down travel of the suspension with limit straps or stops.

elripster

I would do some more investigation. While the vast majority of IFS axle failures are in trucks with front lockers, that is odd.

When climbing that hilll, did you hit any particularly hard bumps? Do you have a brace between the LCA rear mounts? If they start to spread, or even flex hard under impact, that will encourage the CV to slip out. I'm just trying to brainstorm causes.

I should add even though it was stated, the Superlift retains the stock 5" of travel. Limit straps are totally unnecessary. Everyone and their mother at least replaces the bumpstops for about 7" or so. People like me mod the kits for about 12" of travel. That's the first time I've ever seen a shaft slip out. I'd be looking for other causes.

Frank

WATRD

A good point in most cases. In one instance where I saw this happen, the lift allowed the diff to move just enough that the CV was able to hyper-extend. Perhaps there is some play to the diff that you are not easily seeing.

RobG

Thanks Everyone for your responses.

It is clear that something moved more than it should have. I didn't get the truck back until late last night so I haven't had a chance to examine it thuroughly. I think I was in shock when it happened, up until that point the truck was performing better than ever.

I'll start working on it tonight. Hopefully nothing is in too bad a shape and it will go back together with some new boots and grease.

To clarify a few points:
- The front differential was locked
- I was moving pretty fast in order to make it up the hill as my buddy in his Jeep had just taken the hill before me with a struggle and he is better in the sand.
- I may have hit a few small-medium rocks or bumps while moveing fast (30?)
- There is no brace on any of the front crossmembers (there will be shortly)
- I probably had the wheel turned as I was trying to stay on the trail.
- I attached a picture of the trail from a previous visit if anyone is interested. Nothing too radical.

I'll let you know if I find anything interesting.

Thanks Again !!!

Rob