I wasn't really considering an Overdrive for the 2A, due to cost, but it was always on my mind. Then one day back in summer '07 a friend, who works at a 4x4 shop, called and said he'd soon have an OD for sale, $300 if I wanted it. Well I damn sure did, but at that price, I'd have to remove it myself.
So off I go with the tools one day, and with his help, took it off the T-90/D-18 combo that was being replaced w/a newer tranny/transfer case combo.
Removal wasn't going too great, and soon became apparent why. Getting to the "special" nut that holds the planetary gearset to the transmission mainshaft, it was already loose! Bad news, since that's supposed to be torqued to 110 lbs., and is critical to proper operation. Not to mention the small metal particles that kept falling out!
I had a sinking feeling, but took it all home anyway, to scope out thoroughly. I didn't have to pay for it until after examining it.
It was a mess. Because that special nut was loose, the gearsets could move forward & backward at will, and under accelleration/deceleration, had beat themselves to death! One main thrust bearing had disintegrated entirely, and the rollers had circulated around w/the oil, going through all the spider gears! So the spider gears were shot, the gear shafts had beat their mounting holes out-of-round in the planetary hub, so that was shot. The grit from the disintegrated thrust bearings had run through all the other bearings, so they were shot. The syncro didn't work smoothly, because of all the same grit embedded in the brass, so PO had jam-shifted it, and broke the shifter guide pin, and it broke off INSIDE the shift shaft, so they were both worthless etc., etc., etc.
A quick estimate of cost of new repair parts was @ $650. So I took it back, not wanting it, and showed them all the busted parts. Well, in that condition, the PO didn't want it either, so I got it for nothing. After searching the web for a month or so, I found enough NOS parts at discount, plus new parts, to get the repair cost down to around $450-500. That made it worthwhile.