We just got my '87 samurai running today and everything is working good, except for a bad tank of gas. But theres something fishy when you shift or accelerate hard. It's either the t-case or rear axle that makes a sound like gears hitting and it kind of  jerks around, it might not be hurting anything but it's REALLY annoying.
Any help will be appreciated
 Thank you.
       
 
                 
 

Check your rear u joint.

Do you have a locker in the rear end?

No I dont have a locker in there (yet)  . And we checked the rear driveshaft and its bolted on tight when you twist it with your hand it turns about half an inch in either direction, but thats normal right?
Also we jacked it up yesterday and it does sound like its in the rear axle, but I could'nt tell if the clunking noise was coming from the diff or the axle housing. 

Half an inch seems a little excessive to me.  But with the spool back there I might not have as much give in my rear end.

it is probily the rear u-joint cause alot of the new trucks do that also it is just the shims

What do I need to do to fix it will new shims do the trick?