The First Biodiesel Truck Gets Tremec TR-4050 From SST

While the modern automotive age may be slowly turning to automatic transmissions, for many, a manual is still the king. Manual gearboxes are often stronger and more reliable with less complicated internal components, not to mention the fun factor of being directly in control of your vehicles up and downshifts. Silver Sport Transmissions (SST) knows all about everything there is to know about manual transmissions.

As a company that prides itself on high quality and innovation, SST is consistently pushing the envelope of manual transmissions by offering new kits and components for a wide range of vehicles. One of their most recent additions to their extensive product line up is the Tremec TR-4050.

Tremec TR-4050 5-Speed Manual Transmission

On a Tremec manufacturing facility tour, SST’s eyes were opened to the TR-4050 and the ball immediately started rolling. As an Elite Tremec Distributor, SST knew it would be a great unit. Tremec has been building the transmission for over 25 years, though it has not yet been used in the U.S. market. Mostly used in South America, the transmission has been loaded into a wide range of vehicles, including Chevrolet C3500s, Ford F-350s and is still used in brand new Ram 4000s.

Tremec TR-4050 Specs

  • The Tremec TR-4050 is a 5-speed manual transmission with first through fifth gear ratios of 6.16, 3.11, 1.71, 1.00, .76 and a 6.03 reverse.
  • 425 LB-FT OE Rated (based on a 15,000 lb GVWR)
  • Chrysler/Jeep Transfer case bolt circle with 23 spline output shaft
  • Oil Capacity – 3.67 QT
  • High-contact constant-mesh helical gears for maximum strength
  • Die-cast aluminum alloy housing saves weight while offering considerable rigidity
  • Standard right-hand six-bolt PTO offers the ability to run hydraulic pumps
  • The multiple rail internal shifter provides excellent shift feel and performance
  • All forward gears and reverse gear synchronized
  • Advanced synchronizer technology promotes smoother shifting and reduced shift effort
  • Weighs 164 lbs.
  • 19.5 inches overall length
After careful planning, SST worked out an exclusive deal with Tremec and debuted the TR-4050 at the 2019 Easter Jeep Safari in Moab, Utah. We talked with Jeff Kauffman, Vice President of Sales for SST. “The reason SST is offering the Tremec TR-4050 is to fill a specific hole in the US market with a product that has high quality, excellent shift quality and is suitable for four-wheel-drive applications.” The transmission is extremely versatile and can be adapted to a growing number of engines. Just about every popular motor can be backed by it.

The TR-4050 bolted to a Cummins R2.8 with an Axis Industries adapter kit.

Installing The Tremec TR-4050

Diesel trucks and manual transmissions are widely known and accepted combination. The high torque values of diesel burners and the often-extreme duty of the vehicles they are in require a solid transmission to handle the stress. When it came time for the first-ever Biodiesel truck to get a new transmission, the Tremec TR-4050 was an easy choice.

Current Engine List

  • AMC 232/242/258 I6, 304/360/401 V8
  • Cummins Diesel 4BT, 6BT, R2.8, 5.0
  • Ford 289/302/351 (with adapter plate), 240/300 I6 (with adapter plate), Modular V8, FE/385 series (with adapter plate)
  • General Motors, SBC, BBC, LS, LT, 3rd Gen I6 (shares same bell housing pattern as V8)
  • Mopar 318/340/360 V8, Gen III Hemi
  • More to Come!
We caught up with Don Scott, Director of Sustainability for the National Biodiesel Board (NBB) who now maintains the very first test mule truck to run solely on biodiesel in the United States. “The 1991 Dodge Ram 250 was used by the University of Missouri to conduct the first biodiesel testing in the US.” Don explained. “The Missouri Soybean Merchandising Council (MSMC) funded the initial research.” Soybean oil had gone back and forth of being a byproduct of soybean meal for food and oil being the primary use for many industrial purposes.

The project had merits and backing but did not have a large budget. The MSMC and Agriculture Department U of M had to get creative and worked out an arrangement with the Foundation Seed company within the University. Foundation Seed purchased the Dodge to use for their own work within their company and agreed to loan out the truck for the research and development.

All aspects of the project were tracked. A second Dodge had been added to the project in later years and had it's motor torn down for inspection.

After the success of the initial one-year project, MSMC purchased a Ford to use for the promotion of their efforts. Testing continued on the Dodge until 1996. The Dodge was a proof of concept for the project but was still a company truck and was not able to be used for demonstrations and events around the United States. Foundation Seed used the truck as it should be, handling heavy-duty work. Around 2002, the original transmission failed. The truck then sat in a gravel lot until 2019.

There was a brief discussion of the engine being removed and used in a bigger heavier truck. “The Foundation needed a larger truck,” Don said. “So I worked with the University to preserve the truck for posterity.” And so, the revival process began. The Tremec TR-4050 was brought up in conversation which then turned into reality.

After the QuickDraw Brand adapter kit was installed with a new clutch, the TR-4050 was installed.

Don worked closely with SST and linked up with Chad McKinney of QuickDraw Brand to get a premium bell housing kit to mate the new transmission to the biodiesel-powered Cummins 6BT engine. SST works closely with QuickDraw Brand on many of their vehicle specific kits. It wasn’t long before the truck was revived and starting to go on its own show circuit.

The Tremec TR-4050 has all the goods, it has the durability, use in OE vehicles which means is has been testing and validated time and time again, and is still in production. When compared to the NV4500, which has been out of production for many years and has never had a tight and positive shift feel, the TR-4050 is a no brainer. Find out more information on the Tremec TR-4050, exclusively at Silver Sport Transmission.

Article Sources

About the author

Jake Headlee

Jake's passion started at a young age wrenching on cars with his Dad. Obtaining that glorious driver's license sparked his obsession with grease and horsepower, and the rest is history. Soon, he was a general mechanic and suspension specialist, and currently designs and modifies products for the off-road industry. Jake enjoys rock crawling, desert racing and trail running, and writing in his spare time.
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