won`t go into 4 wheel

this is what happened
I had to replace the pass. side 1/2 shaft also the seal on the axle was a little wet so I was going to replace it at the same time. tried to remove the axle but it would not slide out like my buddy said it should (he ownes his own repair shop) it came out a little but no more so I put it back in and just did the shaft.
Now the front axle won`t lock in I pulled the acc. it seems to work and it will not lock in man. by pushing on the fork.
Could somthing have droped off when I pulled the axel ???
The front diff. makes no noise when in 4-high or 4-low just won`t lock in ??????
HELP

I think I found the prob. To pull the pass. side axle you must remove the axle tube remove a snap ring and slide out the axle.(if it would stop snowing-raining I will remove it and see what happned) Thank God for the local Libaray a great ref. section

pulled the axle tube yesterday found the prob. where the pass. side axle goes imto the output shaft theres is a needle bearing the bearing broke apart thus not keeping the axles aligned so the slider could not ingauage the 4WD cost to fix $5.00for bearing and have it pressed into output shaft & $15.00 for oil (picked the bearing up at a bearing shop not the dealer)
Just a heades up to all if this happens to you !!

Help!!!!!!!! My Gmc 4x4 1990 2500 Wont Go Into 4x4 I Am Screwed In The Mountains With Snow
Help!!!!!!!!!!!!!!! Ps I Hate Parts

I hear you,
if the transfer case is shifting and you have 4w low but the 4x4 light not coming on it is most likely the actuator check this link
http://gm-parts-for-less.com/
it would be #8 they also sell a manual locking sysetm check with Summit Racing or 4x4 Supply house