The Demon Automatic 727 TorqueFlite Rebuild

Ccrp 1206 Project Demon Mopar 727 Transmission Rebuild 17

Ccrp 1206 Project Demon Mopar 727 Transmission Rebuild 00

The Demon project is getting closer to track time. Jimmy White of Circle City Hot Rods in Orange, California, lent us a hand and some tools to get the front end mounted. More on that in the next installment.

The Demon project is getting closer to track time. Jimmy White of Circle City Hot Rods in

The adrenaline shakes take over in your left leg as you probe your subconscious for the list of things that will keep your car off the guardrail. In your right hand is the shifter connected to a reverse-manual valvebody in the automatic. With 800 pounds showing on the brake-pressure gauge, you floor the gas pedal, letting loose the dogs and bumping off the rev limiter in the water box. With a slow count to three, you release the button on the line-lock and roll to the starting line. With your foot on the floor you sidestep the brake pedal and head for the rev limiter before pulling the shifter down for the one, two, three. You pass the stripe at 145 mph and lift. The engine freewheels, muting all but the sound of the pebbles bouncing in the wheeltubs.

Our ’71 Dodge Demon project is going to make neck-snapping power courtesy of a couple of Comp Turbos plugged into our eBay Hemi. We briefly considered a modern overdrive, a stick, and even ogled a Lenco on eBay until fabricator Grant Peterson ended that conversation. He was correct. The right move was to stick with the classics on this throwback to the ’70s and bolt in a 727 TorqueFlite. The only car that came close to beating the primer ’55 in the movie Two Lane Blacktop had one, and that’s good enough for us.

The 727 will fit into most Mopar models without this much surgery. In this case, we moved the engine back when we installed the Chris Alston's front frame kit, and the floorpan had to go.
The 727 will fit into most Mopar models without this much surgery. In this case, we moved
Before the build, PA stripped the cores down to be cleaned and inspected. Because the trans uses hydraulic pressure to operate, the case can't have any cracks. If one is found in a high-pressure area, the case must be scrapped.
Before the build, PA stripped the cores down to be cleaned and inspected. Because the tran
This is the high-gear drum. It contains the clutches and steels that are upgraded for additional longevity. The clutches use a heat-resistant friction material from Alto that reduces the amount of slip during each shift, therefore reducing heat and wear. In High gear, all these clutches and steel are under load and producing heat.
This is the high-gear drum. It contains the clutches and steels that are upgraded for addi

The 727 first appeared in 1962 as the “early model” that had a large-spline input shaft and was sometimes operated with a push-button shifter. The transmission that was built for us by Performance Automatic (PA) in Gaithersburg, Maryland, is based on the later ’71 to ’78 model. It has a fine-spline input shaft and, when properly prepared, is suitable for 600 to 700 hp abuse at race car weight and can handle a 10- to 11-second street door-slammer, no problem. Just don’t use the one designed for a lockup converter. The transmission continued in production in various forms until 1991, after which its design was absorbed into newer models.

The Street Smart System

PA Street Smart System kits are designed to make the transmission upgrade for muscle cars and street rods easy. The kits include the transmission, a custom converter, all performance parts, a deep chrome pan with a drain, and a dipstick with a tube.

The Burnout

All burnouts should be started in Second gear, then the transmission should be shifted to Third as soon as the tires start to spin. When you roll out of the water box, lift off the gas. Never blip the throttle. The idea is to avoid shifting with huge sticky tires spinning at a high speed by simply lifting off the gas as you roll out of the box in High gear. Shifting as the tires begin to grip or dragging out of the box in First will rip the overrunning clutch out of the case. Ask us how we know.

How To Shift It

This transmission uses a full-manual-reverse valvebody. That means the governor and kick-down are out of the equation. When you move the shift lever, it shifts. As a safety mechanism, the engine is allowed to freewheel during deceleration in First gear. If you should shift into First at high speed and you are not on the gas, you won’t pull the engine down or lock the wheels. The reverse pattern also pulls down and away from Neutral and Reverse so you don’t accidentally engage them.

Parts List

DESCRIPTION	PN	PRICE
727 small-block Chrysler	PA 13105	$1,999.00
727 big-block Chrysler	PA 13106	1,999.00
10-inch Pro Launch torque converter	PA 13200	695.00

This is the rear drum, that, despite its name, holds the First, Second, and Third gear clutch packs. In First, the clutch pack is loaded; in Second, a band is added; and in Third, the band is off and the High-gear drum is loaded.
This is the rear drum, that, despite its name, holds the First, Second, and Third gear clu
This is the rear drum partially assembled. Here you can see high-temperature Kolene coating on the steels that fit between each clutch in the pack. Kolene sheds heat quicker and makes the steels more stable and less likely to fuse to the clutches. There will be one more clutch and a pressure plate on top of this.
This is the rear drum partially assembled. Here you can see high-temperature Kolene coatin
This is the reverse-manual valvebody. It has CNC-machined fluid passages that change the pattern to redirect the fluid. On the lower left is the shift detent. Everything is checked and repaired or replaced if needed.
This is the reverse-manual valvebody. It has CNC-machined fluid passages that change the p

This is the output shaft. The bearing at the end is replaced as needed.
The overrunning clutch (aka sprag) is normally splined and pressed into the case. Performance Automatic replaces it with a bolt-in version if needed. If the spring and roller go bad, they can also be replaced.
The overrunning clutch (aka sprag) is normally splined and pressed into the case. Performa
The main pump body gets a new bushing and pump gears.

In this photo, the original band is lying flat on the bench, and the replacement Raybestos High Energy band is standing beside it. Not only is it wider, but it also has better friction material for more holding power.
In this photo, the original band is lying flat on the bench, and the replacement Raybestos
With everything back in the case, you can see (left to right) the rear band that holds the rear drum for Reverse with the band and high-gear clutch pack applied. In the center is the sun shell that holds the sun gear and planetary gears. Next is the intermediate band that engages Second gear. All the gears are inspected, and the tolerances are checked. If they are out of spec, they are repaired,
With everything back in the case, you can see (left to right) the rear band that holds the
You want the highest-capacity trans cooler that will fit the car. The guys at Performance Transmission recommend a maximum fluid temperature of 200 to 210 degrees F. A trans that is constantly at 210 is going to wear faster than one that works at 190 degrees F. The most stable reading is from the oil in the pan. PA offers a temp-gauge kit to monitor temperature.
You want the highest-capacity trans cooler that will fit the car. The guys at Performance

This is Tyrone Bryant, putting the finishing touches on the 727 before it is shipped. PA builds all the popular domestic rear-drive transmissions.
This is Tyrone Bryant, putting the finishing touches on the 727 before it is shipped. PA b
To keep the new transmission alive, you need to keep it cool and shift it correctly in the burnout box. Transmission fluid will start to burn, change color, and smell when it gets hot. You can prevent damage by checking the fluid after each run. If it is burning, you'll need to run the engine to pump the fluid through the cooler. If the fluid is overheating on the street, you'll need to make sure you have an adequate oil cooler. Change the fluid with a brand-name Dexron/Mercon 5 at 25,000 miles on the street or with a Type F racing fluid between seasons if you are on the track.
To keep the new transmission alive, you need to keep it cool and shift it correctly in the
The converter is a heavy-duty 10-inch Pro Launch from Transmission Specialties. It has a billet cover, a new impeller hub, a pilot bearing, a turbine hub, and brazed fins and anti-ballooning plates. In the photo is the adapter from Street and Performance that mates the 727 to the new Hemi pattern.
The converter is a heavy-duty 10-inch Pro Launch from Transmission Specialties. It has a b