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Tech Review: ATI Performance Products 4L85E Transmission Package



By Steve Baur

Photography Courtesy of ATI Performance Products

With OEM horsepower levels of 400, 500 in normally aspirated forms and 600 and even over 700 horsepower in supercharged forms these days, it’s easy to understand that finding big horsepower for your street car is not an issue. In modified form, it gets even more wild, as we regularly see boosted Coyote and LS/LT engines producing anywhere from 600-1,000 horsepower at the rear wheels. While the engines can deliver it, the rest of the drivetrain may not be able to handle it, so ATI Performance Products has stepped up to provide a solution in the transmission department with the company’s line of built 4L85E transmissions.

In addition to it’s three speed automatic offerings, as well as its 700R4 and 4L65E transmission options, ATI Performance products saw the benefits that the 4L85E offers in stock and upgraded forms over those transmissions and now offers 4L85E transmissions and complete transmission packages that also include a torque converter, transmission cooler and fan, SFI-approved dipstick, and an optional electronic transmission control unit.

As ATI general manager David Caine put it, “It’s not just about the transmissions, but the individual pieces as well.” It is indeed the individual pieces that strengthen the alright durable 4L85E transmission, and ATI has a long and strong background in developing parts that withstand the most aggressive rigors of racing. Components like this input shaft are manufactured from 300M or Vasco materials for the utmost in strength and durability.


“We’ve been working on the 4L85E transmissions for the past five years,” said David Caine, general manager of ATI Performance Products. “A lot of guys called us for the 700R4, but they couldn’t handle the power that they needed. The 4L85E is basically a Turbo 400 with an overdrive in terms of strength and components. There are many interchangeable parts between the two.”

Caine also noted that the 4L80E transmission, while beefier than the 4L65 that came before it, uses a 4-pinion carrier, versus the 5-pinion version used the 4L85E.

“A two-speed Turbo 400 doesn’t use the 4-pinion, it’ll use the 5-pinion carrier with modifications, and those have been tested to handle over 3,000 horsepower.”

ATI worked early on with Jason Miller of Marlyand International Raceway fame, whose late-model Mustang received one of the first upgraded 4L85E transmissions from ATI.

“Jason’s car was very fast, but he couldn’t get consistent with the stick shift,” Caine told us. “He didn’t want to give up overdrive because he drives the wheels off his car.”

From that experience came ATI’s first 4L85E Street Rod package, which is rated up to 700 hp. That was soon followed by a pair of High Horsepower packages rated to 1,000 and 1,500 horsepower.

Pictured here is ATI’s Ford Modular bell housing that is employed through the use of ATI’s own billet adaptor. The adaptor allows the use of SFI-spec bell housings as well, yet maintain the same overall length of the transmission.

“After Jason’s car, we put the transmissions into straight up race cars,” Caine explained. “The technology has gotten so good and so advanced, these days you pull out your credit card and there’s a pump gas, 1,000hp daily driver engine package waiting on your door step, but the stock transmission wasn’t designed for that.”

The 1,000hp package includes a 10-inch, billet cover single-disc torque converter, 300M input and main shafts, a billet clutch hub, high-energy clutch material with extra clutches for Third gear, and a deep cast aluminum pan for better fluid cooling.

For those with bigger power and torque figures, ATI has its 1,500hp-capable option. It includes an SFI 30.1 Chevy bell housing with adapter installed, a 10-inch billet cover, triple-friction torque converter, Vasco input and main shafts, a billet clutch hub, billet aluminum pistons, a bearing roller case, and a 300M output shaft among other upgrades.

Just released are ATI Performance Products’ new output shafts and an extension housing for 4L80E & 4L85E transmissions. The shafts are made from 300M material with a 4140HT splined hub and are rated to over 1,500 horsepower. They’re manufactured in house and are offered in a standard 4L length, as well as a custom length that, when used with the ATI heavy duty cast aluminum roller bearing tail housing (Part # 701935), makes the 4L85E the same length as a Turbo 400 transmission.

In a world of 1,000-plus-horsepower Coyote 5.0Ls, Gen III Hemi, and LS/LT engines, a 1,500hp-capable transmission doesn’t sound that crazy, and best of all, you get to keep the overdrive!

ATI Performance Products