I thought the same thing, until I noticed that the 310 had split axles and the 312 has a one piece axle/differential. Believe it or not, but the axle broke, it did not twist, but had a linear split/crack and just finally broke. I am replacing the axle, bearings and seals, everything else looks good. Has you know, having a service manual on hand makes it easier to fix dumb mistakes when your have to guess on reassembly. Guess I'll have to rely on a 310 and hope nothing weird turns up. That's why they call me a grease monkey. Thanks IlEngine for trying.