REVERSE: Where it all Began

Every great build starts in Reverse — you look back, learn from where you came, and build from it.

That’s how RedLine Transmission began.

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Ours begins long before diesel trucks ruled the roads — back when Karl was just a kid turning wrenches on hot rods. At fourteen, he was building engines. At fifteen, he had already rebuilt his first transmission.

That spark — the one that makes you want to know how it all works together — never faded.

It grew into a career, a calling, and a company dedicated to the same question that started it all:

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“How can I make it better?”

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That question drives every RedLine build, every test, and every satisfied customer on the road today.

NEUTRAL: The Turning Point

Every transmission hits Neutral before it changes direction.
For us, that moment came eighteen years ago.

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Karl was deep into diesel performance when he bought a “built transmission” from a nationally known company.

It lasted 1,500 miles behind a 400-horsepower truck and FAILED.

When the warranty excuses started rolling in, Karl decided to shift gears.

He tore it down, studied every piece, and rebuilt it himself — stronger, cleaner, better.

That frustration became focus.
Neutral became momentum.

Originally named RedLine Diesel Power, RedLine Transmissions was born out of necessity — a passion project turned purpose.

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Through late nights, trial and error, and countless test runs, we built transmissions that actually hold up.

Not just under load — but under real life.

DRIVE: The Passion That Fuels Us

Drive is where things start moving.

It’s the gear where curiosity becomes direction, and direction becomes progress.

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Karl Mireiter, founder and master builder at RedLine Transmissions, has been chasing horsepower and reliability since he was twelve.

What started as pure curiosity — a need to understand how engines and transmissions worked and how to make them better — quickly turned into a lifelong pursuit of perfection. By fifteen, he’d already rebuilt his first transmission.

Before long, word spread that Karl wasn’t just fixing what broke — he was making it stronger.

That hands-on curiosity became expertise, and that expertise evolved into RedLine’s philosophy:

Don’t just repair — improve. Don’t just rebuild — re-engineer.

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Today, every RedLine Transmission carries that same energy — built from passion, tested with precision, and refined with pride.

OVERDRIVE: Where We Are Now

Overdrive is where everything comes together — power, precision, and purpose working in perfect sync. It’s the gear where you stop building momentum and start owning the road.

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That’s where RedLine is today.

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Originally known as RedLine Diesel Power, our name evolved naturally into RedLine Transmissions — a reflection of what we became known for: building performance-driven transmissions that deliver power, reliability, and results. (Don't worry, we still offer all sorts of upgrades for your truck!)

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What started as one builder with a passion for doing things right has grown into a trusted name across the diesel community. With more than  2,700 transmissions on the road and 18 years of testing, building, and refining, RedLine has earned its reputation for craftsmanship and confidence.

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We’ve built transmissions for every kind of driver — from tow rigs and work trucks to hot rods, sled pullers, and 2,000-horsepower monsters. Each one is built by hand, tested under load, and backed by experience that only comes from years behind the tools.

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Overdrive is more than a gear — it’s our standard.

It means never coasting, never cutting corners, and never letting you drive away without that coveted firm shift.

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Because for us, performance isn’t a product — it’s a promise.

Built For People Like Us

We know what it’s like to depend on your truck — to need it to start, pull, and perform every time.

We’ve been the ones stranded, frustrated, and let down by “big name” builds that didn’t deliver.

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That’s why we do things differently.

We test harder, build smarter, and stand behind everything we make.

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When you run a RedLine Transmission, you’re not just buying a product — you’re joining a brotherhood of drivers who believe in craftsmanship, reliability, and doing things the right way.

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Because at RedLine, we’ve lived every mile of this story.
And we’ll keep building transmissions that prove it — gear after gear.

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RedLine Builds It Better. Always in Gear. Always Moving Forward.

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What We Believe

• If it’s worth doing, it’s worth overdoing.

• We don’t guess — we test.

• Every customer deserves honesty and craftsmanship, not excuses.

• We build every transmission like we’ll have to drive it ourselves.

RedLine isn’t a brand built on marketing — it’s built on experience, accountability, and the relentless drive to build it better.