Wooffinn

Hey guys, wooffinn here, I'm a bit of a virgin in this area so be gentle! :P I'm a mechanic and fix Mazda's but I don't see a lot of late model stuff; it's a bit rare over here.Just a quick gearbox problem I've encountered. A friend and I recently fitted a 13B and box[non turbo gear] from our series 4[ your early gen 2] into his 808 wagon. Bloody flies but he's managed to munch the gearbox. On buying one from the importers from a almost identical RX-7[so we were told anyhow] that everything was identical except for one minor detail - the imput shaft, while being the same diameter, the splines were different. Our new one has fairly coarse splines while the old one was the usual mazda fine spline. They said it was from an Non turbo Rx-7. anyone seen this? Is it a turbo box? Any help would be great!