i think your problem is something else. either it being that something is going on with the case to cause the gears to not mesh right. or maybe you just so happened to get a bad batch of gears...kinda a long shot but it happens. you can almost guarantee that a stock output will be the first thing to break after big tires and 4.7s. specially if your not bound up. make sure all the c clips are on where the gear shafts go into the bearings. they send the gear without them and lots of people forget to take their old ones off and put them on the new set. since their helical cut gears.. if the clips aren't in it can cause the gears to walk off the bearing a bit. wouldn't take much either. also if they were forgotten everything would work completely fine until there was enough pressure for them to move.

unless i missed that you are running a chromo rear and front output then this is either shitty luck or i think something else is wrong.

also (not taking to you pumpkin toy) but you cant even compare a 4.7 to a stock 2.28, completely different with the amount of stress it sees. also there are no other brands out there besides t.g.. and obviously mc makes the top of the line gearsets.

..... COMPLETELY TRUE... this is where i was headed with my line of questioning...

honestly i had pumkin toy figured for anything BUT a newbie, and the c- clip thing only breifly crossed my mind as something a newbie would do, but hey, i make stupid mistakes or over look things sometimes

very possible (considering how fast they broke after you got the new set)
missing c-clips on the input and counter shaft gears like "-Matt-" posted here--> http://board.marlincrawler.com/index.php?topic=78097.msg918917#msg918917

but if this was true, if you were going forward, the helical gears would cause the input to go towards the grill and the counter shaft towards the tailgate, am i Right? because i have seen on one occasion where the counter shaft has been pushed so far off the 63/32 bearing, it started milling away at the #2 housing and pushed the counter shaft cage bearing up against or (nearly up against) that ledge behind it but i believe (if my memory serve me right )the gears themselves were fine and practically untouched. i know for certain the small set of teeth on the counter were perfectly normal looking

this leads me believe it's more of an alignment issue, which is VERY rare in the RF1A Transfer Case, but helical gears by design can not take hardly any misalignment at all

so make sure both your dowl pins are there, not too deep...and TIGHT!!!... no wiggle wobble


also, as a side note, it's not a good idea to assemble a t-case with silicon. gaskets are a lot thicker than silicon (relatively speaking) and it CAN also create problems  inside the case, like oiling and tolerance issues... and don't use both! just make sure the gasket surfaces are completely oil free, brake clean and a rag should do it. sometimes people will take the front of the reduction (or #1) housing to a belt sander to true up the gasket surface... there by causing the input and counter gears to get closer to the #2 housing, tightening the tolerance between the main shaft, and the back of the input... i have seen those two surfaces come into contact before so it's not impossible but something to watch out for....(this is probably not YOUR issue but its good common knowledge)