bernie the bolt

Help im the sad owner of a p38 2.5 and must be mad this car has cost me a fortune its a good job i do the labour myself since oct 10 ive replaced the door locks/window regulator/fronr radius arm bushes/head gasket/front wheel bearings then the engine plus a new turbo and fuel pump and know the auto box has gone it seems to stick in 3rd gear but only when it feels like all gear changes are smooth when it works ive changed the filter and the oil so do i take the plunge and replace the box or do i buy a td6 vouge