I have a 1993 Vitara, 4 door 1.6l  4wd.
A few sdays ago I had it in 4wd and then it just jumped back into 2wd and the lever slammed down. I tried 4wd again and it gave me the same problem but his this time when it jumped out  I heard a clicking in the front hubs, I have automatic locking hubs.

Any suggestions, I think the hubs may need some sort of servicing. How do I go about this??

First off, you're not using 4wd on the road are you? Check the gearbox and engine mounts if one of those is broken it can allow the tcase to rotate a little more than it should causing the lever to foul on the body.

As you describe it,and the lever slammed down (went back that is?) ,I think what you are saying is that you had 4H and it went back to 2H,cause it would be impossible to go from 4L to 2H.

Well,I dont know if its relevant,but I ll tell you this:
A similar problem I had once ,was when I had 4L and I trying to go over an obstacle,suddenly the 4WD stick (lever?) went back to N (Neutral)(2H->4H->N->4L).
That day it happened 4-5 times.
The reason for that was that at the mount of the 4WD lever there are some lets say metal fuses that hold it to its place.I had 1 (or two? cant remember what my mechanic told me) broken.So when I was on 4L trying to overcome obstacles(which means stress) ,the 4WD lever was popping out ,back to N.
Hope this helps.

The reason for that was that at the mount of the 4WD lever there are some lets say metal fuses that hold it to its place.I had 1 (or two? cant remember what my mechanic told me) broken.So when I was on 4L trying to overcome obstacles(which means stress) ,the 4WD lever was popping out ,back to N.

Anyone else ever heard of metal fuses holding the T-case lever in place? I Would like more info on this if someones got it.

I sometimes use the 4wd when the road is wet and the back seems to spin out when cornering and  going up the hill. What is the deal the 4wd and pavement.
(Bear with me I am newbie)
Thanks for the heads up. I will check the mounts as you have said. I am just getting to reply as Hurricane Ivan knocked out power and I was stuck in the hills for a week.