When I bought my M37 about a year and half ago. I had the tranny go out after about 60 miles. The PO chipped in and paid for another tranny. The synchro was demolished on mine when I tore it down to see about a rebuild. I jumped the gun and found an old style one out in WA., shipping was a bunch. I got lucky, I tore it down and put new gaskets and seals in and the synchro was still in good shape. I should have looked to the newer style. To the point, I looked high and low for another synchro assemble and none are available for the old style. The synchros are available along the all the other parts for the new style which bolts right up and nothing has to be changed as it's a direct replacement. I have thought about having a set of synchros machined since I have one half of the old one to copy that didn't get destroyed. I also thought about having several sets made for those who may need them, it's just not on my high priority list. It would be nice to find a blueprint to go from also.