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 it...no 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
Shifter-bar
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:
 
www.motivegear.com
www.4wheelersupply.com
www.stangcrazy.com

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 remove.....it 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 axles....ie: 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.