O.d.

Simple Logic that the mainshaft turns in any gear, it is what turns the driveshaft. The only time it does not turn, is in neutral. I love the O/D, but hesitated to recommend because of the 500 ft lb of torque. That is where the factory went with the 18 spline input shaft. I do not have anything in that range. So I do not have first hand experience. The O/D is not a cheap or cheaply made transmission. The early ones are very good but did get cheaper as time went on. The best thing to do to make them stronger is to reduce the float, I call it slop, by bushing the aluminum main housing or just replace the main housing with a cast iron housing with the press fit countershaft bores and standard countershaft. The theoretical locked input gear seams irrelevant in the practical world. I can cruise all day long at 70-80 MPH with mine and it is as smooth as my A833 4 speed.