Well here goes....when I shift from 4w back to2w it seems to drag and then drops out with a thump. My sidekick is a 93 with manual hubs (my first 4x4 with maual hubs) my Dodge had shift on the fly. So I have been given three different versions of the shifting sequence and been told that the fact that the last owners idea of using 215/70 on the front tires and 215/75 on the rear could be causing the problems.Tires are to be replaced soon anyway. The writing on the instruction plate on my console been worn off so I was hoping for a little help or instruction from some of the guys with more experience using maual hubs, or even a pic or image of a instuction plate I can read would be great. Thanks   

Your problem is because of the tires, even the same size tires that
are worn and smaller on either the front or the back will cause this
same issue, the way to stop it is to stop, shift into reverse and back
up to relieve the windup in the driveline, which causes the gears to
hang up and not come right out of 4WD

Wild

Ohh and if you have the hubs locked you can shift on the fly so long
as you are not spinning the rear tires at the same time as you shift, but
to get 4 low you need to stop first then shift to low range, if it's an auto
trans then you need to shift into park or the trans will spin the t-case and
grind the gears, if you are really fast in your shift, you can use neutral but
if it's not fast the trans will spin the t-case and you will have to turn off the
engine to get into park or either gear of the t-case

 Thats what I needed to know thanks. I guess I will have to get my new rubber befor I go off road again, better reason to get them sooner than later Thanks

You know, this would never happen on a samurai.  If it is bound up, the gear shifter just wont move.  I'm way more experienced with sammys and toyotas, but my sidekick does this too.  the shifter moves as if nothing is wrong, but it takes time to actually shift untill such time the binding has stopped.

So for you sidekick gurus, this is my guess since I have not torn into a kick tcase yet.  Is the shifter spring loaded?  so when you shift the spring applies pressure untill such time that it over comes the binding?  I can see the benefit of  as would reduce people forcing the shifter causing damage and wear.

I always thought that this was a weird characteristic.

Yes the 4WD shift fork has a spring on it to allow the
lever to move even if the gears are bound up.

Wild

i guess that I am a good guesser...

 Thanks for the info guys. Put some new "matching" rubber on last week and used the 4w in the snow we had this week and like the man said "your problem is because of the tires". Work perfectly hope all the repairs on my Sidekick are as simple and now I know exactly what it sounds like when it binds up and pops out of 4w. Always new  4x4's should have matching tires and but never actually experienced what could happen when they didn't match. Lucky for me I didn't break anything.