How to Rebuild a Super-Turbine 300 (ST-300) - A Pictoral Essay

All of the valves are spring-loaded, so each is retained with a pin.

 

The Detent Valve is different - it's retained by a Kick-Down Solenoid. The solenoid is a valve that responds when you floor the gas pedal, causing the transmission to down-shift.

 

And here's the completed assembly. If you look closely between the oil passages you can see the five valves (arranged vertically).

Put this assembly aside for later.

 

Next up is the pump body. If the valve-body is the brain, this is the heart. It provides the oil pressure that shifts the transmission. The left side of the picture is the planetary gearset I mentioned earlier (before assembly).

 

The pump body has it's own valves. Here is the boost valve, spring-loaded like the others and retained with a C-clip.

 

Next is the Timing Valve. It simply drops in place and is retained when the two halves of the pump body are put together...

 

...like this. Both sides of the pump body are placed together. A daisy-chain of hose clamps around the perimeter keeps the halves even while the bolts are tightened.

As with all of the other sub-assemblies, put this one aside for now.

 

Now onto the transmission case. First up, install the parking pawl.

 

Next, install the manual shift mechanism and parking lock bracket.

 

Now find the reverse piston, oil the seal and fit the piston into the back of the case.

 

Then install the piston return springs

 

Followed by the spring seat.

 

Remember that home-made clutch compressor tool? You'll need it again here. Compress the spring seat and install the snap-ring retainer.

 

Then install the rubbery cushion ring into the piston groove

 

Now, the reverse clutch pack. As with the forward clutch, it consists of alternating steel and lined plates. Start with a steel plate. There is a notch in one of the ears on these plates. That notch goes in the 5 o'clock position as shown.

 

Just like the forward clutch pack, add a lined plate (soaked in ATF), a steel plate, a lined plate... until you run out of plates

 

The final plate is a thick steel plate. Instead of a notch, it has a dimple on one ear. Again, install with the dimpled ear in the 5 o'clock position.

The whole works is retained by a large snap ring (not shown) that fits in a groove alongside the final steel plate.

 

Now fit the Reverse Ring Gear. It has grooves that engage the lined clutch plates.

 

Make sure the ring gear has lined up with all of the clutch plates and is fully seated, as shown.

 

Remember that Planetary Gear Set from the very beginning? The one I forget to photograph complete? Here's what it looks like as you install it in the transmission case. The long tail extends out the back of the case for the driveshaft. The outer edges of the pinion gears engage the inside of the reverse ring gear.

In operation, everything (including the Reverse Ring Gear) spins as one. When the Reverse Clutch Pack engages, the Reverse Ring Gear is locked and the pinions roll backwards against it, carrying the planetary with it and making the car go in reverse. Think of a circus performer walking on a barrel while facing backwards and you'll see how it works. Pretty neat!