About Us

Welcome to RedLine Transmissions

Dodge/RAM trucks lined up in front of RedLine Diesel Power Transmissions


RedLine Diesel Power DBA RedLine Transmissions are your Cummins and Duramax specialists! Our custom-built automatic transmissions are all manufactured in-house. Our experience delivers more power to the ground, guaranteed!


Redline Transmissions is Northeast Ohio’s source for high-quality transmissions, performance, and repair. 

We offer:
• Automatic diesel transmissions for Dodge/RAM Hellcat/SRT and Chevy/GM.
• Complete diesel truck performance and repair, Cummins and Duramax—engine
• Fuel Injection Components
• Air intakes & gauges 
• Hot Rod diesel pickup truck builds from mild to wild and beyond!


Our reputation is known for our problem-solving skills specializing in the powertrain department. In-house transmission building is just one service that has separated RedLine Transmissions from its competitors. We build transmissions that fit your application, regardless of your power level. As a result, we can build a transmission that will hold and prove to be more efficient. Many transmission re-builders make this claim, but our experience will get the job done correctly.


Our team is experienced and experts in automatic transmissions for Dodge/Ram Cummins, and GMC/Chevy Duramax engines. We are also skilled in performance upgrades for Dodge and Chevy trucks.


RedLine Transmissions builds a full line of upgrades for light-duty diesel trucks, including HD transmissions, billet-covered torque converters with custom stall speeds, custom turbochargers, and more. Performance upgrades designed and built for reliability with increased driveability available for Dodge RAM and GM diesel pickup trucks.


Our custom transmission packages feature billet components and the most substantial gear trains available. All light-duty types of diesel trucks are covered. Ask us about our performance upgrades!


A simple philosophy is at the core of our business. Your truck will receive the same quality install or repair we would do on our vehicles. Diesel trucks are our passion. It is in our blood. It is what we were born to do. We are proud to say we have been in the industry for 22 year with over 16 years of experience and over 1800 transmissions built. If you would like to learn more about our history, click here.


Not only do we build superior transmissions, but we are pros at installing them. Our transmissions are installed in our shop located in Medina, OH which is a suburb 25 minutes south of Cleveland. If you are unable to bring your truck to us, we have the full capability to ship the transmission to you. We are are able to ship anywhere in the contiguous United States excluding California, New Mexico, Oregon and Washington.

RedLine Transmissions services transmissions for Dodge RAM Cummins 2500 and 3500 including 47RH, 47RE, 48RE, 68RFE and Chevy Duramax Allison 1000/2000. We ship to Alabama, Arizona, Arkansas, Colorado, Connecticut, Delaware, Florida, Georgia, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Jersey, New York, North Carolina, North Dakota, Ohio, Oklahoma, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, West Virginia, Wisconsin and Wyoming.


“Not all transmissions are created equal”


RedLine Created by Karl M. Mireiter

Learn about the history of our company why Karl started building transmissions

I started RedLine Diesel Power in 2007. The goal was to fulfill a need within the diesel industry on the power and performance side. Every transmission is built with 17 years of experience and knowledge behind it. We are constantly testing our products to give you the very best. have RedLine Diesel Power strives to build you the highest quality transmission, period.  We have well over 1,900 customers (and counting) using our transmissions every day whether it be for a tow vehicle, daily driver, hot rod, drag racer or truck puller. You can be confident we have a transmission build that will hold up to your needs and put the power to the ground. 

Before diesel pickup trucks were popular, I had a reputation of building fast cars.  I started out working on hot rods at the age of 14. By 15, I had rebuilt my first transmission. I have always been passionate about automobiles.  This has fueled my passion to advance the diesel industry by offering a quality product at a reasonable price. 

We started building diesel automatics 17 years ago out of necessity.  I had purchased a “built transmission” from a nationally known company and it last only 1,500 miles behind a 400 hp truck.  After going round and round with them with their “warranty”, I decided to fix it myself.  Through trial and error (and a lot of research and development) I have designed a build-to-suit your needs from an improved stock build all the way up to a 2,000+ hp monster. 

Not all transmissions are created equal. There is a big mis-conception out there about the words “built transmission”.  Throwing a shift kit in the transmission and a new torque converter does not make it a built transmission. Most shops will sell you on this theory, and tell you it will hold up to anything. They couldn’t be further from the truth. Unfortunately, you will be lucky if it holds up for a month.  What good is their warranty if you have to take it back ten times.

In 2023, we changed the company name from RedLine Diesel Power to RedLine Transmissions.  Since transmissions are what we are known for, it seemed like a natural progression. We will continue to offer performance upgrades such as head studs, turbos, injectors and aftermarket fuel systems to make trucks stronger, since horsepower runs in my blood.

At RedLine Transmissions , I custom build you a transmission with parts we have machined just for our transmissions. Whether it be a billet shaft, lever, spring, valve, converter, strut, clutch, steel, etc. It is made from the highest quality materials and in the USA.  You get the owner building your transmission, so quality control is very high. How many shops can you go to and have the owner build your transmission? Not very many.  Whether you have a Dodge Cummins, Chevy Duramax, or a MOPAR, I will build you a transmission that will exceed your expectations.  Please call today to get an estimate and schedule your appointment.  See you soon.

Karl M. Mireiter

Check out some of our recent projects HERE!


Yes we have a dog named Diesel. What else did you think his name would be? If you come to the shop he is sure to greet you and say hello.