Our L4630 GST transmission case is cracked on the back for the second time. A mechanic welded a crack the first time, 18 mos ago, and now there is a new crack that he says can't really be mended. Plus several of the six bolt holes that bear the load have stripped over the years and have had to be tapped and replaced by larger bolts and there just seems to be chronic problems with the thing. My guess is the design of the back of the transmission case is not strong enough to support the loads put on it by our Taesung backhoe attachment. Bottom line is I am considering getting a new transmission case from Kubota ($1008) as I can't find a good salvage one, and transplanting the whole gearbox/diff (which work fine) into the new case, and putting it back in. (Later we will fabricate a subframe or something to provide better support for the backhoe so all the load is not on those six bolts and I am not worried so much about that.) The question I have is: how difficult a job is it, after removing the old case entirely, to do the transplant of the GST & diff to the new transmission case? I am not a mechanic, and although I lived most of my life in California, I am now retired and living in the Fiji Islands where I do volunteer work managing an organic farm that has several Kubotas. I assume I will need the work to be done by a senior mechanic with a good head on his shoulders and I will find one but I have heard GSTs are hard to work on. Is this an extremely difficult job? Thank you for reading this far. - Tim in Fiji