The problem with the Transfer drive gear on 5 speed boxes relates to lack of oil getting to the mainshaft of the 5 speed. Early LT230 box used roller bearings on the input gear, in 89 LR changed these to timkin taper bearings which happened to pump oil away from the shaft. The fix from LR was first to fit a plate behind the pto cover with a cresant shaped piece of steel welded to it to catch and drip oil on the end of the shaft. The real fix came in late 96 when they decided to drill 4 x 3/8 holes in the spool of the input gear between the drive gear and the pto dogs, at this time the transfer case serial#suffix was changed from E to F to denote the mod. This problem causes clonking when changing gear not whining. You can remove the gear in situe to check. Put both boxes in nuetral remove the pto cover and bearing housing and the the gear will slide out with a giggle. If it is not drilled and has wear on the shaft splines and gear splines you need to determine your next step. First you can pack it with hi temp wheel bearing grease to stop it clonking and sell it. Second if the splines are not to bad you can drill the gear and stop any further wear. Third you can replace the gear with new drilled unit, this will 1/2 the back lash and limit further wear. Third rebuild the the box with new mainshaft and drilled gear and forget it. There are lots of 5 speeds in Australia so I've rebuilt / modified a few
