gravely zt52hd w zt3100 purging issues

i recently pulled a zt3100 transaxle apart that wasn't working lookin for wear items because i heard a clicking like a gear was stripped when i spun the tire,after pulling it apart i looked at all the gears etc and they were fine,i pulled the pulley off and the gear there on the pulley was stripped smooth,got a new replacement gear & fan assembly and refilled with oil etc let set overnight,did the hydro-gear purge recommendation neutral to engaged several times with no luck except the tire will very slowly rotate.i even lifted back of the unit and left it overnight almost straight up and down hopin it would let some air escape with no luck.anybody have any suggestions i could try to get this thing back working? my next step i'm gonna try is unhook the reservoir tube and maybe try to force some oil into it somehow which i don't have any confidence in but getting desperate.any advice or ideas greatly appreciated

http://apache.ariens.com/cgibin/ctrg0005?SESSIONID=0.8169340101205662&Site=GRAVELYS

you can download service manual for your unit & locate the information you need by entering model & serial numbers

yes,i tried that site yesterday for the service manual didn't exist,i tried the link again for the owners manual today & it came up,it was somewhat helpful it showed the drain plug which i've tried to take out with no luck,someone has used the wrong allen and stripped it & i've done everything i can to get it out w/o taking a chance on cracking the housing,i just cranked it and backed the filter off a tad hoping to bleed any air out there but it seemed clean flowing no air bubbles that i saw,i'ma go tinker with it now see if that helped,thanks

i had this thing apart and bone dry and that cavity that is also sealed inside the casing is my guess is the issue,nothing else has worked so i'ma take it back off of the unit & try and guess the way to turn it to maybe get the air to escape either thru the pump or maybe the other direction. if this doesn't work i'm just gonna replace the pump this is gettin aggrivating

got it off upside down,pump pointing straight up pull pump cover slap full,no oil i'm thinkin it has more issues than just spun pulley gears