CPT says that if a Mustang's...
CPT says that if a Mustang's engine mounts are worn, a block of wood between the engine and K-member crossmember is needed to hold up the engine once the transmission is removed. While the block was dutifully installed in Ricky's car, the mounts proved fairly fresh, the engine did not sag much, and the block fell out. In that case, the wood wasn't needed.
The narrow OD band is replaced by a higher-quality, wider, 2-inch unit, and the line pressure is increased via drilling several holes in the valvebody plate. This firms the shifts, and other valvebody work allows safe full-throttle upshifts into OD.
Curing the weak, two-piece input shaft is accomplished by using a vastly stronger one-piece shaft. This eliminates breakage concerns, but the trade-off is that a lock-up torque converter can no longer be used. CPT makes its own non-lock-up converters, which is what Ricky received. This results in a gain of approximately 400 rpm at freeway cruising speeds, so fuel mileage may fall a tick, although historically this hasn't shown up much. The better acceleration and other efficiencies from the upgraded transmission probably offset the higher freeway cruise rpm-or rear-axle gear-ratio changes, power adders, and so on made at the same time as the transmission upgrade mask this relatively small effect.
CPT's 10-inch converter brings the foot-brake stall speed to 2,600-2,700 rpm, although CPT says you may see 3,000 rpm without creep on a sticky dragstrip and good tires.
Finally, a proper, high-quality 19-row oil cooler is fitted for the sake of dura-bility and consistency.
Gutting and building an AOD...
Gutting and building an AOD also follows typical automatic practice. The pan is removed and the filter and valvebody (shown) are unbolted and removed. Under the valvebody is the OD servo piston, which is picked out with a small screwdriver or prying tool. CPT uses a bench-mounted vise to hold the tranny and allow easy rotation of the work. It's a huge help.
All told, CPT figures the average performance gain is 0.750 second and 3 mph in the quarter-mile, provided you have the traction. The increase in applied low-end torque is considerable, so the tires and suspension need to be up to the task.
As with all major improvements, getting this amount of work done costs more than just lunch money. The CPT Extreme Duty transmission retails for $1,999, the CPT Mega-Torque 10-inch converter is $549, and the oil cooler is $189 with fittings and brackets. Toss in tax, installation, and possibly shipping, and getting an AOD into shape can be a $3,000 proposition. The reward is a CPT transmission that will shift worlds better and happily bang out the thousands of shifts behind big-power engines.
Predictably, after driving it home, Ricky was excited about his new gearbox. The big deal is the fast, positive shifts in a streetable package. "It's not a neck snapper," he says. "It's solid, not laggy-just a good shift in all gears ... It has some stall to it-not too much ... It bangs the shift at 5,100 rpm every time at full throttle ... It chirps the tires at 4,600 rpm on the one-two shift. The car definitely feels faster and is obviously more responsive."
With the bottom of the trans...
With the bottom of the trans handled, the next step is inside the bellhousing with a puller to remove the pump as was just done here. Then the remainder of the innards are pulled out through the front of the case. A succession of large snap rings are encountered, but there are no nasty hardware surprises.
What's inside the case is...
What's inside the case is mainly the 1-2 planetary and clutch pack, which is being pulled out here, as well as the reverse and direct drums. All are removed and loaded through the front of the case, and none require special tools.
At the transmission's rear...
At the transmission's rear is the tailshaft housing. It simply unbolts. Underneath is the governor-it requires a light tug with a puller to get it off the tailshaft. There are no performance adjustments necessary on the governor, so it is simply removed and replaced as part of the CPT upgrade.