When it comes to trying to run low 8's, you can have all the horsepower in the world, but your rear end and transmission need to be bulletproof. So when it came time to select a transmission for Project Grandma - our infamous '78 Malibu - we made a call to the transmission experts over at TCI. They recommended one of their Pro-X Powerglide transmissions, and you're about to learn more than you ever dreamed about what it takes to make a serious 'Glide.

TCI builds their Pro-X transmissions to handle horsepower numbers well into the 2000 range. The question is, how can you build a transmission to handle this kind of power when it was originally built to handle 200-300 horsepower? Good question! To fully understand the Pro-X, there are a few little things that must be discussed first. Let's take a look at why the Powerglide has become so popular over the years, and check out some of the other aftermarket Powerglide choices from TCI to compare to the Pro-X.

Why a Powerglide?

The Powerglide was GM’s go-to automatic transmission back in the '50s and '60s, and usually found a home behind 250-300hp V8 engines, but it also sat behind V6's and a variety of other power plants. While originally manufactured with a cast iron case, in the early '60s GM developed an aluminum case version for use in the compact Chevy II. There are differences between the versions used in cars and trucks, but that’s another story.

Why did it develop into a serious race transmission? Two reasons. One, being a 2-speed, it works well in dirt track, circle track, and drag racing applications. Second, the parts are commonplace, as it's easy to modify and work on. In short order, the GM Powerglide is the transmission of choice for the who's who of motorsports.

OEM vs. Aftermarket Transmissions

TCI refers to the Powerglide as the true workhorse of racing transmissions. They understand that this gearbox can be tweaked ever so slightly to fit into almost every budget and racing style, and they offer several different options for the racer who wants to put a Powerglide under their seat.

First, you need to choose your case.

This is the first step, no matter what other options you desire. TCI is always searching the country looking for usable Powerglide case cores that they can refurbish. They also offer the Dedenbear case (an aftermarket case used in the Pro-X transmission) and the ATI Super Case.

Here is an example of a custom transmission. This is an aftermarket case with a TCI reworked GM valve body being installed in it.

After you choose your case, you can set the transmission up with the gear type best suited for your power levels. Talk to TCI, they will make sure that you get the right one for your combo.

As for the valve body, TCI has many options for full manual shifting, and transbrakes with different delays. The same goes for your gear ratio. There are ten different choices for the ratios in their Powerglides. Again, TCI can steer you in the right direction to make sure that the transmission they build will be the right fit for your vehicle. They will consider things such as racing application, horsepower, and driver preference to make the best choice.

Numerous options are available for the oil pan as well. TCI has transmissions with oil pans made from steel or aluminum, stock depth or deep pan, and even one with a special coating the helps to reduce the oil temperature.

TCI puts every unit that they manufacture and sell through a series of three dyno sessions, starting with the valve body, in order to ensure that all of their transmissions are of the highest quality. First it’s dyno’d. Then it’s hydraulically checked in every gear, both with the transbrake on and off, in order to ensure that it is able to hold the correct amount of pressure. Once it passes this test, it is moved to the next stage.

Next, the transmission is dyno’d without the valve body to check for any leaks. This test weans out any hidden problems, such as lip seals cut into the clutch packs or leaky sealing rings. The transmission is run in all moving gears, checking for leaks. This is also the first check to make sure that the transmission works correctly.

The final dyno test is really the true test for the transmission. The valve body is bolted on, along with the filter and oil pan, then the transmission is strapped to an axle line dyno and is put through a test that includes running it in all moving gears. Afterward, the main line and reverse pressure are checked again. Next, the dyno is set to run for a certain amount of time, to ensure that the performance of the transmission will remain the same as the oil heats up.

Finally, the dyno results are printed on a dyno card that is attached to the transmission. This is done to validate that the transmission sitting before you passed TCI’s rigorous tests. If at any time the dyno alerts the operator to a problem, the transmission is torn down to determine the issue and correct it.

For most, the prep work and dyno checking are really the determining factors in choosing an aftermarket transmission. Try asking the guy at the local junkyard for a warranty on the used OE transmission you are buying from him, then try to act surprised when he gives you his answer.

TCI Pro-X Transmission - TCI's Top Level Aftermarket Transmission

TCI understands that the Powerglide works well because of its simple design. When it came time to design their top of the line Pro-X Powerglide, rather than reinvent the wheel, they chose to promote the transmission’s strong points and beefed it up where it was weak.

TCI went through every part of the transmission, with the goal of making it capable of handling the high horsepower demands of drag racing, and they met their goal. According to TCI's Scott Miller, the Pro-X transmission - such as the one used in Grandma - can handle horsepower numbers in the 2000 range. This means that we can throw all of the nitrous we want into our 555 Edlebrock engine and don’t have to worry about cooking the transmission.

Here is the quick run down on the Pro-X:
  • Designed for race cars regularly running 6.70-seconds, 220+ mph in the quarter mile.

  • Ringless-Style Genotor Pump

  • X-Wide Kevlar Band

  • PRO-X Ringless Input Shaft

  • HDT Coated Aluminum Deep O-Ringed Pan

  • Hi-Flow Filter System

  • HDT Coated Dedenbear Bearing Case

  • 10-Clutch Hi-Gear Bearing Drum Kit

  • 1.98, 1.80, or 1.65 Straight-Cut 12DPI Super Set Planetaries

TCI is able to put so much trust into their Pro-X transmission because they only use high quality parts. However, as many of us familiar with the Powerglide are aware, the case is often the OEM transmission's weak point. Therefore, you won’t find an old junkyard case being used for the Pro-X.

Aware that cracking is a common issue with Powerglides, TCI turned to Reid Racing for their damn near bulletproof case. Not only are the oil pan flanges thickened to stiffen the case, Reid also beefed up the oil pump area to prevent the front of the case from flexing (which can cause numerous problems, including gear misalignment and breakage) under high horsepower.

Reid used enough heat-treated aircraft grade aluminum to make the bell housing beefy enough for SFI 30.1 certification. There is no need to mess around with a flex plate shield, because the bell housing itself can withstand and contain any failure.

Another modification made by Reid involves the inner insert that is installed into all of the cases. Again, the designers at Reid outdid themselves, and the case earned an SFI 4.1 certification - meaning you don’t have to use an external shield.

The transbrake is the final component that makes this case the one and only choice for TCI and their Pro-X transmission. The release time of the transbrake was reduced while redesigning the oil passages, thereby giving a more instant release. The case is also pre-drilled for a double dump transbrake.

The transbrake can be adjusted by the simple turn of a screw, located next to the solenoid in the rear. By adjusting the screw, you can determine how hard it hits on release. We can use this feature to really dial in the launch on Grandma.

Inside the Case

Now that we've covered the case, it’s time to look inside - starting with the reverse piston.

The reverse piston slides right in the bottom of the case. While many racers drill a small hole on the outer part of the reverse piston (to aid in allowing aerated fluid to escape the cavity behind it), TCI leaves it intact, drilling a series of holes into the housing to release any trapped air.

Next, the friction plates are installed. Although these little plates don’t seem like much, they keep your transmission going. A set of lock rings holds them in just the right way for the springs to apply the correct amount of pressure, and when the case is full of fluid, the lock rings control the plates locking / unlocking the transmission.

TCI's Pro-X has Alto Red Eagle clutches, made from heat-treated colleen steel that mates up with a Steel Pioneer clutch hub. The aftermarket ring gear comes next, followed by a Vasco gear set that matches the power and handling strength of the rest of the transmission.

Once the friction plates are in, TCI measures the clearance of the clutch packs and ring gears. This step ensures that everything is aligned and installed correctly.

The planetary is next. When TCI first started building beefed up Powerglides, they stuck with the OEM style sun gear with a spiral cut design. Through testing and consistently trying to improve their products, they found that using a 180 straight cut design gives the transmission more strength with less power loss.

TCI matches that up with a 4140 steel billet output shaft and carrier assembly. Next in is the drum, followed by the input shaft. At this point, TCI measures the depth of the shaft. Getting this right is what makes a ‘tight’ transmission, and if need be, they will space the shaft to get it to sit just right.

When you put the input shaft that TCI uses in these transmissions next to an OEM version, the differences are crystal clear. The aftermarket input shaft is bigger, it's made from better materials, and it's definitely capable of handing more power. Scott Miller tells us that both the planetary and input shaft used in this transmission are the same, part for part, as those used in their transmissions for cars with over 2000hp. "Any time you have a car making more than 500 horsepower, you should use a hardened input shaft," states Miller.

Next, it is time for the front pump. This part seals off the main components of the transmission from the front. TCI uses their Ringless-Style Gerotor Pump on the Pro-X line, to make sure that there is plenty of fluid flowing at the right times. The output shaft is also installed at this time.

Once the billet dual ring servo is in the Pro-X, it is time to install TCI's custom valve body. Using their knowledge of what makes a good transmission, the team reworked the valve body to provide cleaner shifts with less chance of failure. Provisions are added to accommodate the transbrake, and the valve body is converted to a full manual shift - giving the driver full control of the transmission.

Finally, the oil pan and filter are installed. TCI uses their deep aluminum oil pan on the Pro-X for several reasons. It holds more fluid, and the larger surface area helps to dissipate as much heat as possible. Additionally, this pan acts like one big heat sink, catching plenty of air passing under the car to help do its job of cooling. Finally, it is coated with TCI's HDT (Heat Dissipation Technology) Coating, to lower oil temperatures by promoting heat transfer from the oil to the pan.

Making The Full Package

“The other components you use with your transmission will greatly affect its life and performance,” Miller tells us. Therefore, we looked once more to TCI for the other associated components. They have a complete line of torque converters that are designed for use in their transmissions, and also make shifters, coolers, and even have a line of transmission fluid. All of these components have been designed to do one thing - make their transmissions perform at their highest level.

Transmission Cooler

Miller informed us that when it comes to extending the life of your drag racing transmission, the cooler the oil is, the better. To keep the temperatures under control, we picked up one of TCI’s Max-Cool Transmission Coolers.

These coolers use a plate and fin design, which TCI claims "reduce transmission temperatures by 33% over tube-style transmission coolers." We like it because it provides a nice clean look, and thanks to the hardware that is included, is very easy to mount almost anywhere you want. We picked a nice spot in the rear of the car, under the trunk. To ensure that their coolers gets enough air flow, TCI equips them with a 10-inch electric fan. They are offered in four different sizes, and we went with the biggest one. As Scott says, you can never have it too cool - but operating temperatures should be right around 180-200 degrees if you are checking.

Torque Converter

To complement their line of transmissions, TCI developed a Pro-X style torque converter. These converters are offered in a 10-inch or a 9.5-inch (like ours). Choosing which one to use simply depends on the amount of horsepower that you have. The 9.5-inch is good up to about 2000 horsepower, while the 10-inch is for the guys pushing the 2500hp mark.

A billet sprag assembly, which TCI claims is unique to this converter, sits inside of the saucer-shaped component. While the heat-treated steel turbine drives and hub assemblies help increase strength, the real claim to fame for this converter lies in its stator combo.

Made from high-strength steel, this piece is made to vary the stall and add strength for extreme applications. The converter can also be set up to match your car's performance. If you're spinning the tires off the line, you can soften the hit of the converter with the stator combo, and if you need a little more grunt off the line, adjustments can be made for that as well.

To keep everything inside of the converter, TCI uses a forged mounting cover that is coated with their Heat Dissipation Technology Coating for temperature control. They claim that this will provide greater durability and consistency.

Outlaw Shifter

TCI recommended one of their Outlaw Shifters to give us control over the Pro-X. This is a universal shifter that can be mounted very easily in any car. They are offered with gate plates to work with most American 3 and 4-speed transmissions, as well as the 2-speed Powerglide (like ours). The pistol grip handle can also be ordered with a micro-switch that can be used to control things such as transbrakes or line locks. The reverse lockout feature means that it is NHRA/IHRA certified - because bumping a shifter into reverse at the wrong time is never a good thing.


In order to get our Pro-X into the car, we knew we were going to have to make something from scratch. We started by mating the transmission up to the big block Chevy that we were sticking under the hood. After doing a dance with the cherry picker, the engine / transmission combo was bolted in - or at least the engine was. This would tell us exactly where to run a crossbar to serve as a mount.

Mike Ryan, aka The Fabricator, carefully welded an I-end onto the ends of a Chrome-moly tube that would later become the mount for our transmission. Mike welded two tabs to the inner frame rails to link the bar to the chassis, and bolted it using some trusty Grade 8 bolts.

The mount was made from some 1/8th-inch steel, that Mike welded into a three-sided cradle for the transmission mount to rest in. Then we bolted in an Energy Suspension Polyurethane GM Transmission mount, which would help hold our transmission in place, yet still give us some flexibility when it come to the shakes.

In all, the TCI Pro-X Transmission is a great choice for anyone making serious amounts of horsepower and needing a transmission just as serious. Its simple yet bulletproof design makes it one of the most popular choices for a transmission. We found it to be the perfect fit for Project Grandma, and with the availability of swap kits for this transmission, it could easily find its way into your next project as well!





Energy Suspension



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