Any thoughts on my maxi rear diff.

[swamp]

I went out on the weekend, my rear maxi wasn't working, I pulled off the
actuator. The fork was working but the locking collar would not budge, it was stuck in the unlocked position.
I pulled the diff out tonight to chase the problem, the short side locking axle needed a bit of force to free it from the diff centre, the locking collar has a few burrs on the face that meets the diff and but I could not find why it was not sliding on the splines.
Also the long side axle isn't looking the best at the splines where it meets the diff. See attatched image.
http://www.flickr.com/photos/40469897@N07/3722698199/
The line of the splines are distorted fom twist.
Should I keep using it,keep it as a spare or put in with my collection of trophies.
I had thought I may have a bent housing, but I would only be guessing.
Any thoughts?

[Bush65]

The twist is due to torque loads exceeding the elastic limit of the material the axle is made from.

The torque capacity of rover axles is low because they are small in diameter.

[ISUZUROVER]

The twist is due to torque loads exceeding the elastic limit of the material the axle is made from.

The torque capacity of rover axles is low because they are small in diameter.

What John said. In short, you will need a new axle. No harm in keeping that one as a spare for emergency use though.

[swamp]

I pulled out the short side tonight, although the diff end spline looks good,
there is a bend in the locking collar splines which is stopping the collar from sliding freely.
This axle is only 18 months old done one winch comp and a few social trips.
When locked the twist load goes from the spline at the end of the locking collar to the drive flange, as opposed to unlocked where it goes from the diff splines to the drive flange.
This will make it three axles in 2 years .
I thought I would break cw+p's before bending axles.

[Bush65]

I pulled out the short side tonight, although the diff end spline looks good,
there is a bend in the locking collar splines which is stopping the collar from sliding freely.
This axle is only 18 months old done one winch comp and a few social trips.
When locked the twist load goes from the spline at the end of the locking collar to the drive flange, as opposed to unlocked where it goes from the diff splines to the drive flange.
This will make it three axles in 2 years .
I thought I would break cw+p's before bending axles.

Some of the problem is shock/impact loading. The axles need to absorb the energy from the shock loads by rotational flex (just like a torsion bar or coil spring in a suspension system).

The axle material has a limit to how much it can be twisted (this is called strain) and not fail or suffer permanent deformation. It has another limit, which is stress that should not be exceeded - this is related to torque and diameter cubed (and for fatigue, greatly influenced by stress raisers).

Now the energy that can be absorbed is related to the strain and volume of material - so the length of the axle comes in here (longer axle absorbs more energy - larger volume).

So you need larger diameter axles, or reduce the shock/impact loading. One option is toy centres and 30 spline axles in rover housings, but there are other non-rover options.