ok im about to try to change the rear output shaft bearing in my 87 truck. Ive never done this before and need advice frome someone that has. Im changing the bearing because i can move the drive shaft up and down about half and inch in any direction. the trnsfer case hase 7 bolt on the rear retainer plate if this helps.

 

Am i here all alone.

 

Have you pulled this case out of the rig yet? You will need a press to take off and replace it. You may as well plan on rebuilding the whole case while you are at it. If the bearing is as bad as you say, there will be a lot of metal floating around in there and has started to tear up other parts also.
Good luck.

 

I'd agree with this assessment. Have torn two down a little while ago, there's a lot of things to inspect in there. Fortunately for me, mine were in great shape inside.