Hi Anji, Yep same box, only things I know of that may change is the RRT2 boxes have a needle roller layshaft, but a bush could still be used if need be-just not a standard one- and gear ratios for different models,
Hi AnjiYou probably looked casting number 66-3141. It is part number 66-3140 and belongs to 1949-62 B/M rigid and plunger, different to A models box.Markku
There's one on the UK Ebay site at the moment. Use the following as your search GEARBOX CASE 42 3006