Late-model transmission have come a long way in performance. Not only do we have more gears to improve fuel mileage, but they are also capable of handling the greater power coming from modern powertrains. Unfortunately, the internal designs that make them great in stock applications sometimes become the weak point when the power level goes up, and the rigors of racing only exacerbate the issue. Then it’s time to step up to a racing transmission for durability and reliability.
With a TKM-built 5.0-liter Coyote engine, Brett Barber-ported cylinder heads, a 3.8-liter Whipple supercharger, and a stock ECU tuned by Rob Shoemaker, Leticia Hughes’ 2018 Mustang GT makes over 1,300 horsepower to the rear wheels and was in need of a more durable transmission option. (Image courtesy of NMRA)
NMRA racer Leticia Hughes has been steadily improving the performance of her 2018 Mustang GT and has been racing it in various classes over the last few years. The 5.0-liter Coyote engine in her Mustang has been upgraded over that period and horsepower has gone from the mid 400 range at the crankshaft to over 1,300 at the rear wheels. She had been using the original 10R80 10-speed automatic transmission and despite having it built to its fullest capability, Hughes eventually found that it wasn’t reliable for the power level of the engine and the racing she was doing. As she intended to compete in the NMRA’s 8.60 Street Race category for the entire season, she approached her sponsors about moving to a Turbo 400 transmission.
Step one in building a top-shelf Turbo 400 transmission involved using a Reid Racing Super Hydra 400 case. These are SFI-certified and often required by racing sanctions depending on the class and e.t. a vehicle may be running.
“We needed the most reliable option with moving the NMRA 8.60 class,” Hughes explained. “Anything beyond 1,000 and the 10R80 becomes really unreliable. I went a personal best on one pass, ran again and ate the transmission. At my horsepower level, the Turbo 400 is the superior transmission.”
The 10R80 did well and Hughes had it fully built to ensure it was durable. Her car is still registered and capable of street driving, so the overdrive was a good choice, but the car’s power level and increased track presence was pushing in the opposite direction.
“The combination of the physical nature of the 10R80 and the software in the stock ECU that controls it are the main issues. The computer can override the tuning calls all on its own.”
The key to holding huge amounts of horsepower and torque are in the friction materials, and this build utilized Raybestos Powertrain steels (PN 357) and its Turbo 400 clutch pack (PN RCPBP-03), which are components designed solely with the rigors of racing in mind.
With that, she reached out to Whatever It Takes Transmission Parts, Raybestos Powertrain, and Transtec for help in assembling a bulletproof Turbo 400.
“There had been a lot of talk about the Turbo 400, some people were running it in her class,” said Rodney Peters of Whatever It Takes Transmission Parts. We sponsored her last year and are proud to be a part of her racing team. We enjoyed putting the unit together and had two master builders on it and I even got my hands on it.”
Hughes’ Turbo 400 is what Peters referred to as the ‘Holy Grail” of transmissions.
“It’s all billet material inside and capable of 1,500 horsepower and up. Headed up by master tech Bill Anthony aka Dr. Evil, the Turbo 400 build commenced and as a longtime partner with Raybestos Powertrain, the WIT Transmission team utilized the company’s Gen II Blue Plate Special friction clutches and steels.
“Last year, she had the 10R80 and ran our GPZ material,” said Raybestos Powertrain marketing manager Nick Truncone. “She’s in the natural progression of a racer and starting to hit higher horsepower. When she wanted to go to the Turbo 400, we had a product ready to go for that, as well. The Blue Plate Special has been a drag racing staple in our lineup for a long time,” Truncone explained. “A lot of people aren’t familiar with the fact that we’ve been making these parts for years. They were originally developed in the ‘80s for Lenco transmissions specifically for drag racing, and they are now in over 20 transmission applications. Our current material was upgraded around 2005-06.
Keeping the transmission fluid clean and free of debris is essential for optimal performance. For this task, Raybestos Powertrain supplied its TH400 Brass Transmission Screen Filter (PN 515732).
The WIT Transmission team took no shortcuts with the build, and Peters expects it to last all year.
“I told the guys that I don’t want to see the transmission come back,” Peters said. “We even dynoed it at 4,500 rpm and we don’t normally dyno them that high, usually just around 1,500-2,000 rpm.”
Hughes is also sponsored by Transtec, which supplied a number of parts used in the new Turbo 400 that performed exceedingly well in its on-track debut, where Hughes made it to the final round of competition and took home the runner up points.
“It far surpassed anything we expected, Hughes told us. “We tested on Wednesday before the event and raced for five days in a row—that was a big deal for us, race competitively, go to the finals, then run personal best the next time out. It proves why this was the best choice.”
The team at WIT Transmissions assembled the Turbo 400’s internals using the Raybestos Powertrain frictions and steels. Peters told us that they have been partnered with Raybestos Powertrain for over 20 years and use the company’s products in every type of build.
After the event, Hughes returned to her home in Kentucky and a subsequent track test netted a personal best elapsed time of 8.28 at 170 mph. She plans to contest the remaining five races on the NMRA schedule in her bid for a class championship.
If you are in need of a more durable transmission option, then the Turbo 400 might be the solution for you, and companies like Raybestos Powertrain and WIT Transmissions can provide the internal components and expert assembly.
