John Kilgore Super Lite TH400 Racing Transmission








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PATC Offers The John Kilgore SuperLite TH400 Racing Transmission.

"Everything works quicker.
The ET's are quicker, reaction times are quicker,
60 feet times are quicker,
quarter miles are quicker, everything is faster."
- John Kilgore

PATC offers the John Kilgore Superlite TH400 Racing Transmission. This is a three speed racing automatic that's stronger, lighter and quicker than a C4 and less power robbing for quicker ET's. This light weight transmission is based on the legendary Turbo 400 but has been redesigned with super lightweight internals to reduce drag and speed-up shifts. The key is in the direct drum that weighs a full five pounds less than a C4's and 15 less that a C6. Though dramatically lighter than the C6, the Kilgore transmission offers as much or more capacity. The 5.0 Mustang race application is a snap with the available small block Ford bell housing.

Although the SuperLite is based on a GM TH400 transmission its very low parasitic losses make it a natural for the small block Ford Mustangs. It's a must for Super Stock and Stock drag race cars to help them accelerate quicker than ever!

1991 Mustang 5.0

In the Superlite transmission the forward & direct clutch assembles are in one housing and always rotates with engine RPM. The complete housing assembly weights just 12 pounds and with aluminum steels it can weight as little as 9 pounds. That means it takes far less horsepower to run the transmission, so more power is available for acceleration. This is not rocket science! Less energy used by the transmission and more energy is available to the rear wheels!

Lighter Parts = Quicker Starts

Assembling a bullet-proof GM TH-400 with a little help from noted automatic transmission specialist John Kilgore.

It's surprising how one particular make of transmission will dominate a certain drag racing class, or segment of the sport. For example, highly modified versions of the GM Power Glide are the veritable backbone of the upper echelon NHRA / IHRA Sportsman category's like Comp, Super Comp and the Super Gas classes.

But what type of racing automatic is best suited for “door cars,” the kind which compete in the Stock, Super Stock, Super Street, or even the Pro 5.0L classes, cars which traditionally have less torque and horsepower at their disposal along with the added weight? Sun Valley, California transmission specialist John Kilgore happens to think it's his version of the GM Turbo 400 three-speed-automatic known as the “Kilgore Super-Lite,” and we're going to tell you why.


Like everything else having to do with drag racing, sheer weight or scientifically speaking “enertia at rest” greatly affects sixty foot launch times and a cars overall elapsed time, not to mention the longevity of a race cars power train components as a whole. And how do you achieve quicker elapsed times as well as reduce component breakage? By reducing weight, plain and simple!

NHRA Super Gas / Super Comp racer “Jimmy G.” is a firm believer in John Kilgore's “less (weight) is better” philosophy and here's why.

“The thing that I think is so cool about John's “Super-Lite” version of the GM TH-400 three-speed-automatic transmission is the fact that has taken and significantly reduced the weight or rotating assembly of parts that you have to “turn” to get a car to launch and accelerate quickly off the starting line.”

“For example, your average 3800-pound LS-1-engine Chevrolet Camaro or Pontiac Firebird will produce 300 ft / lbs of torque and will consistently run 11.50's all day long. However, due to the sheer mass of these vehicles the OE transmissions in these cars are prone to failure.“

What's the alternative? Many of these racers have switched to the more durable GM Turbo 400 three-speed-automatic transmission but not without problems.

“The stock GM TH400 three-speed-automatic transmission has cast iron forward and direct drums. These drums are stopped when the car is at rest and begin to turn when you accelerate. The forward drum weighs 12 pounds and the high gear (rear) drum weighs 13.5 pounds which (depending upon actual gearing) is turning backwards 80% of the engine speed. On normal street driving applications this function happens slowly and doesn't require a great deal of horsepower. However, things change at the drag strip where things happen so much quicker. The power losses become dramatic!”

“What John did was remove the direct drum entirely and he replaced it with a lightweight stamped sheet metal clutch module.” That's the key to the success of the transmission. You no longer have that heavy drum to turn and you can get out of the hole quicker and faster without sacrificing valuable horsepower.

In the process Kilgore has taken the TH400 to the next level by offering all kinds of different gear ratios across-the-board. And that's particularly good news if you're a Ford or Chrysler racer. Different companies manufacture bell housings that will adapt a GM TH400 three-speed-automatic transmission to your particular type and make of engine.

Obviously one of the most popular swaps is a Kilgore SuperLite three-speed-automatic transmission bolted up to a 5.0L engine or 5.8L engine in a late-model Mustang.

“The C-4 can only handle so much power. All you have to do is change the bell housing and the flex plate, set up the torque converter properly and you can use one of John‘s Super-Lites!”

And now the “gospel” according to automatic transmission guru John Kilgore!

“First of all this transmission was NOT designed to compete with the aftermarket GM Power Glide. It was designed as a direct replacement or upgrade for any of the four-speed-automatic transmissions, 700R4 / 4L60E equipped vehicles out there competing in either the NHRA or IHRA Sportsman classes as well as in the local E.T. brackets.”

“These transmissions can be setup with first gear ratios from either 2.10:1 to 3.08:1. We also have available, probably the fastest responding transmission brake in the industry which use second gear clutches in the trans brake instead of high gear clutches. That means we don't have to install a large vent in the high gear to have the brake release quickly.”

John Kilgore continued.

“Obviously the lighter the rotating weight the better the transmission is able to respond. The energy requirements to run the transmission are directly related to the time you have to spin the parts up. If you have a lot of time (like on the street) it wont require that much power. But if you don't have a lot of time (like at the race track) it takes a TON of power. It's almost by the square. By reducing the overall weight of the internal workings of the transmission the “movement of inertia” from the center-out has been reduced dramatically, at least by one-inch.”

Kilgore cited a more relative example, in layman's terms that is.

“If you're familiar with watching ice skaters, when they do “spins,” as they spin, they pull their legs and arms in, and they tend to go faster. Now, no one gives the skater anymore energy, it just takes less energy to turn in a smaller circle, and go faster. Then when they want to stop, they put their arms and legs out and slow down. That's exactly what “moment of inertia' is all about. That's why the closer (you are) to center the better off you are!”

In relation to drag racing successfully overcoming the moment of inertia also has its benefits.

“If you were to stay in low gear for 2 seconds, it might take 10-horsepower. If your try to do it in 1 second it might take as much as 100 HP. It's really parasitic to spin an automatic transmissions internal components quickly. That's why GM Turbo 400's have a bad reputation for taking a lot of power to operate only because in drag racing applications you're trying to turn the transmission too fast, too quick!.”

“One of the more attractive features with the Kilgore Super Lite is that you can stay in low gear longer, which means you can accelerate longer in first gear maximizing horsepower all the way through the engines power band.”

“Since this transmission does not have a direct drum, you don't have to spin a 13 pound weight backwards in low gear. You turn about 3 pounds worth of weight mass backwards in low gear instead. It stops, but it's a LOT easier to do so because it's so much lighter, and closer to center.”

John can also equip his transmissions with a “deeper” 2nd gear ratio that will allow these gearboxes to accelerate or “pull” harder in 2nd gear, much more so than a stock TH-400.

“When in 1st the direct (drum) assembly and the second gear clutches are spinning backwards. Then when you shift to 2nd, the whole assembly stops. And then when you shift to 3rd the clutch pack, clutch hub and the inner race of the 2nd gear sprag requires about 4 1/2 pounds (weight) to go into 3rd gear as opposed to 13 pounds stock. Again, the rotating mass is much smaller in diameter which equates to less power to accelerate the parts of the transmission”

With just half the rotating weight, Kilgore Super-Lites are THE lightest of all three-speed-automatic transmissions regardless of where they come from. For example. The forward and direct drum in a stock GM TH-400 weighs 28-pounds, while John Kilgore's whole system weighs twelve.

“Basically, I've taken a three-speed-automatic transmission which left the factory rated at 550 ft / lbs stock and I've increased the torque rating to about 900 ft / lbs at half the weight!”

More good news! Kilgore Super-Lites are also fully ‘field serviceable,” making them THE automatic transmission of choice for serious door slammer racers.

Kilgore's Super-Lite three-speed-automatic transmissions retail for about $4495.00 without trans-brake feature and $4995.00 with trans-brake feature (setup with the gear ratios you specify) through participating Kilgore SuperLite retailers like Performance Automotive and Transmission Center.

TH400 Super Lite without Trans-Brake
TH400 Super Lite with Trans-Brake

Now let's take a closer look at the actual parts themselves. Then we're going to follow through a typical Kilgore Super-Lite three-speed-automatic performance transmission buildup!


1. Shown is John Kilgore's stamped-steel “Super-Lite” clutch module which houses the forward and direct clutch packs. This piece replaces the heavy cast-iron direct drum, and weighs practically nothing. This unit allows him to upgrade from stock cast-iron friction bands to lightweight, durable, #200-grit friction bands, making for a much more efficient, and lighter unit.

2-3. This is the clutch module with all the Alto Red Eagle clutch packs and forward clutch piston assembly installed.


4. Here we see the OE cast-iron factory assembly which weighs close to thirty-pounds and the stamped sheet metal Kilgore Super-Lite assembly which weighs approximately 12 1/2-pounds.

5. In this photo we see the 2nd gear clutch module with the one-way clutch for 2nd gear mounted onto the back of it.

6. This exploded view shows the Kilgore Super-Lite clutch module, Alto Red Eagle clutch packs, the “steels,” the clutch hub, and the direct piston assembly all joined together.

7. This view shows the forward clutch assembly installed inside Kilgore's Super-Lite stamped sheet metal drum or module, clearly showing the Red Eagle direct clutch packs installed.

8. Shown is the Super-Lite clutch pack (steels & frictions,) which is smaller in diameter than the stock GM TH-400 clutch packs.

9. John Kilgore points to the Super-Lite Planetary Gear layout showing the forward clutch hub (right,) and the direct clutch hub, (left,) along with the Kilgore Super-Lite direct piston. assembly.

10-11. Here are both a 2.10:1 1st gear ratio for the Super-Lite, and a 3.08:1 2nd gear set along with the corresponding drums.


12. Setting transmission line pressure is handled by one of John's line pressure valve. Each turn represents a 10 pound increment.

13. This is a view of Kilgore's custom valve body, electric trans brake module, line pressure valve and trans brake assembly, which John touts as being the best in the business.

14. One of the beauties of the Kilgore Super-Lite is that with the right adaptor you can use this transmission with practically any popular American V-8 engine. Shown is an automatic transmission adapter for the 5.0L Mustang V-8.

15. Kilgore Super-Lite transmission buildup begins with Jimmy G. installing the Sun Gear drive tube into the TH-400 case.

16-17. Next comes the installation of a series of four neoprene lube seals on to the center support of the transmission. There are a total of four from top seal to bottom seal.


18. Next he installs the center support into the actual TH-400 transmission itself.

19. This installation of the center support is followed with the installation of a spring-steel snap ring which holds the center support in place.

20. Shown is the series of four Raybestos “Green Waffle” clutch packs which he will be installing inside the transmission.

21-22. Each clutch pack is individually installed inside the TH-400's case, and then a spring-steel snap ring is used to secure the clutch pack assembly in place.


23-24. Next, comes the installation of one of John Kilgore's center support intermediate clutch snap ring tab which secures the snap ring in place inside the case. This has always been a problem area in stock TH-400's.


25-26. Here's Jimmy G. installing the transmission module inside the Kilgore Super Lite-TH-400 case.


27. He uses a special transmission builder's tool to check the end play off the back of the transmission pump. A reading of .005-.010-inches end play is ideal.

28. The next order of business is to torque of the transmission pump bolts to 18 ft / lbs.

29. With that done, he flips the transmission over and begins installing Kilgore Super-Lite brake valve and trans brake solenoid into the side of the TH-400 transmission case where the vacuum modulator normally goes.

30-31. This is followed with the installation of a Kilgore spacer ring for the low reverse band and the actual band servo cover itself. This is followed with final torqueing the bolts to 30 ft / lbs.


32-33. Here we see the magic fingers installing the center support bolt which gets a final torque to 20 ft / lbs.


34-35. Next comes the installation of the Kilgore Super-Lite valve body itself using a pair of alignment pins. At this juncture the separator plate and gasket are also installed.


36. With everything in place he torques the valve body to 10 ft / lbs of torque.

37. The next order of business is the installation of the Hi-Flow (transmission oil) filter on to the bottom of the valve body itself.

38. He then buttons up is work with the installation of an 8 quart cast aluminum TH-400 transmission pan which is held in place by a series of 3/8 inch bolts.

39. Last but not the least, on goes the TH400 tail shaft housing using six standard 3/8-inch bolts.

40. And here we see John Kilgore himself dyno testing his latest creation. Items checked on the dyno include line pressure, the trans brake release is tested, overall operational testing for shifting quality and efficiency is checked, as well as checking the unit for leaks during cool down. Then and only then is a Kilgore Super-Lite shipped to the waiting customer.

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