idler shaft 60 series transfer case

In a word no, but you can do it in the truck.
You will have to drain the oil from the transfer and gearbox (not sure but some Tojo idlers when removed allowed the gearbox oil to come out BTDT).
Remove the rear tailshaft, out put flange and nut and then you will be able to remove the rear half of the transfer case and replace the O ring. Be careful on taking the back half off as quite often the idler will come with it.
Alternatively if it is only a very slight weep drain the oil and then clean around the end of the idler with carby cleaner, acetone etc and use Clag or similar to seal it externally.
Usually if the idler is starting to weep it is a sign of wear and you might be up for a few new bits.

Brummie Pete

O-rings can ware or go hard with age. If the transfer box does not have huge milage then the rear O-ring of the idler shaft can be replaced with out dismantling. Purchase the correct O-ring (Toyota) clean around shaft, remove retaining locking tab on the back of the transfer box that holds the idler shaft in. Very carefully ease the idler shaft out just enough to see the O-ring, remove old one and install new, carefully slide shaft back into box, may need to gently tap home. Be "very" carefull not to pull the shaft out to far or you will be have to dismantle the transfer box to reinstate thrust washers. If the vehicle has very high milage and the shaft has never been replaced I would recomment it be overhauled.
Its easer to rebuild in the shed before it fails than out in the sticks.

Pete.