roundman

Being a shiftless automatic kind of guy, let me shed some light on this discussion. I know that the early AOD and AODE trannys used a two piece input shaft with the smaller inner shaft splined directly to lock up in the torque converter for direct drive with no slippage whatsoever. This eliminated the higher speed slippage problem prone to automatics that hurt gas mileage and contributed to heat buildup in the fluid. Both 3rd gear (1:1) and overdrive are driven off this inner shaft to maximize gas mileage. Drawback to this is you lose the torque multiplication of the torque converter in both these two gears since you are essentially locked up to the engine just like a clutch car would be. The rpm shift points at WOT on these earlier autos was controlled by a TV cable from the throttle linkage to the tranny that changed the line pressure in the tranny with changing throttle position. this cable can be adjusted to increase the max rpm at which the tranny will shift when at WOT but I could never get more than 4,500 rpm from mine stock. the newer trannys are controlled electronically so you need a chip or programmer to change the WOT shift point on them. the best investment you can make if you have an auto tranny is to add an aftermarket transmission fluid cooler as the stock one in the radiator just can't get the job done properly when running high performance from your auto tranny. you can get a real good one for less than $100 and it will pay for itself in keeping the fluid cooler to reduce wear and tear on the clutches and bands in the tranny. I use a B&M racing tranny cooler myself with my full manual valve body Art Carr Extreme AOD tranny with a 2,500 rpm stall and the tranny never gets above about 160 degrees after I make a pass down the strip shifting at 5,300 rpm with 4.57 rear gears crossing the finish line at 6,200 rpm in 3rd gear.