Technical Information:
Pilot bushing Tool Applications:
T5 transmission tips below:
Rebuilding  the T5 Transmission
'83 CJ7
This started out as an input-shaft bearing replacement.  Its wear was allowing the front-shaft to wobble, contributing to clutch chatter and pilot bushing wear.  The telltale sounds are gear-rattle when starting out, and/or clutch howling or vibration at higher speeds. The bearing is replaceable without opening the transmission up....but, the trannny has to be free of the clutch and engine;  just unbolt the bearing housing from the front of the transmission. This is an aluminum part...inspect the tube extension for
gouges or heavy wear from the  throw-out
bearing..consider replacing it with a steel version. 
While the tranny was out, might as well just rebuild it.  It has 95,000 miles on heavy off-road abuse.  Inspection showed no detectable gear wear;  maybe the syncronizers, some...but, a great deal of wear on the shifter detent-plate, which is pressed into the bowl on top of the rear-housing.
rear housing
Detent plate
Detent-plate, bottom view
detent closeup.
Notice the heavy wear on the detents.  Replacing a worn detent-plate makes your transmission shifter feel like new.  I couldn't get a plate, or a shifter-bar, from Chrysler without buying the entire housing ($300).....however Medatronics, in Florida, with some association with Tremac, has these parts....these guys build the ruggedized T5's.  Phone # 561 447 9594.  They are on the web, also, but,a phonecall works better.  Several other outfits indicated that they also sell these parts:

If you do this replacement, be sure to inspect the shifter-bar post for wear, as well as the detent ball.......also, be sure to use a good locking-adhesive along with pressing in the new detent plate.   The plate is somewhat difficult to has to be knocked out from the underside.   Be careful....I think that the aluminum rear-housing could fracture around the detent-plate seating hole.....pressing it out would be preferrable. 
post....follows the detent slots
T5 transmission tips below:
The two-piece axle blues:
Most everyone with an older Jeep has had the blues of a spinning hub, resulting from a sheared woodruf-key.  Here are a few pictures of such an event in a 1983 CJ7....problem fixed with one-piece the hub is integral with the axle shaft.
Posted April 2008     Warning to GM LS(x) engine owners!!
All GM LS engine crankshafts have a soft plug in the rear of the crank which seals an oil galley hole gun-drilled during manufacture....

This tool will NOT work with this crank, since it will quite probably punch a hole in the soft plug....I am fabricating a tool mod with a slide hammer attached to remedy the problem.        Tune back in May for availability.