Unlocking and locking - 4WD > 2WD

[dazza]

Over the last week or so, I started hearing a squeaking coming from my front end (72 K10 SWB), but only at lower speeds, about 20mph and below. It would come and go, but got worse. So yesterday I jacked it up, new bearings and u-joints ready to replace, and started reading a few things in two different manuals. Both manuals were persistent on the fact that once the truck is in 4wd, it must be shifted back into 2wd BEFORE you unlock the hubs. Now I started thinking about 3 weeks prior when I had it in 4wd and put it back ino 2wd, and yes, I unlocked the hubs first! So I took the truck back out, locked the hubs, put inot 4HI, it drove fine, no squeak. 4LO barely moved. Back to 4HI - ok. Shifted it to 2wd, unlocked the hubs and it drove great - NO Squeaking.
My question is: Did I do some serious damage?? I probably drove it this way for 6-800 miles. Is there a proper procedure for going in and out of 4wd? I know some 4x4's you need to reverse after going back to 2wd, is this required?

Any insight would be helpful.

Thanks,
Daz