Top Notch Transmissions builds high-performance transmissions for truck owners, diesel enthusiasts, and anyone pushing power levels beyond what the factory designed for. Whether you are running a tuned 6.7L Cummins behind a 68RFE, a supercharged LT4 behind an 8L90, or a deleted Power Stroke behind a 10R140, we build transmissions engineered to handle the power and the abuse without leaving you stranded.
A stock transmission behind a tuned engine is a ticking clock. The factory clutch packs, valve body, torque converter, and shafts were designed for stock power levels and a customer who drives to the office and back. The moment you add a tuner, bigger injectors, a turbo upgrade, or start pulling heavy loads at elevated power levels, those factory components are operating past their design limits.
A standard rebuild restores your transmission to better-than-factory condition with upgraded components that address known failure points. A performance build goes further. Every component is selected for the specific power level, torque curve, and duty cycle of your application.
The torque converter is the single most important upgrade in any performance transmission build. Factory converters use stamped steel covers, thin lockup clutch material, and welded hub assemblies designed for stock power. A performance converter uses billet steel or forged aluminum construction throughout. Triple-disc clutch assemblies replace the factory single-disc design, providing dramatically higher clamping force and friction surface area. The stall speed is tuned to match your engine’s torque curve — diesel trucks typically run a tight 1,600 to 2,000 RPM stall that puts the converter in its efficiency range at low RPM where diesel torque lives. Anti-ballooning plates prevent the converter body from flexing under high-RPM load.
The valve body controls every shift event and clutch engagement in your transmission. Factory valve bodies use aluminum valves in aluminum bores, and those bores wear oval over time. In a performance build, we install steel valve replacements, oversized bore sleeves, and hydraulic recalibration kits that raise clutch apply pressure and firm up shift timing. The factory lube circuit — often running at inadequate pressure levels — gets corrected to deliver proper lubrication to clutch packs under high-load conditions. On newer transmissions like the 10R140, full billet valve body packages are available that increase main line pressure by up to 60 PSI over factory.
Factory clutch packs use friction material calibrated for noise and vibration targets, not for holding power under high torque. Performance builds use competition-rated friction material from manufacturers like Raybestos and BorgWarner that provides significantly higher heat resistance and clamping capacity. Where the factory used the minimum number of friction plates, we add additional plates to increase total surface area. On a 68RFE, the overdrive pack goes from five frictions to six or seven. On a 10R140, the F-clutch goes from four plates to five. That additional capacity is the difference between a transmission that holds and one that slips under load.
Above approximately 700 pound-feet at the wheels, factory input shafts start to twist and shear. This is a sudden, catastrophic failure with no warning. Billet chromoly input shafts provide two to three times the torsional strength of the factory casting. Output shafts, reaction shaft supports, and clutch drums are also available in billet for extreme-duty applications including sled pulling and drag racing.
Heat kills transmissions faster than torque does. Every performance build includes a cooling system evaluation and upgrade recommendation. Factory transmission coolers — especially the radiator-integrated designs — are marginal for stock power and completely inadequate for elevated power levels. External air-to-oil coolers with 25,000 to 40,000 BTU capacity, thermal bypass valve corrections, and deep aluminum pans that add two to four quarts of additional fluid capacity are standard recommendations. The additional fluid volume acts as a thermal reservoir that absorbs heat spikes during hard pulls.
For trucks that tow at or near rated capacity on a regular basis. Upgraded clutch packs, valve body recalibration, billet torque converter, and cooling upgrades. Designed for reliability under sustained heavy load rather than peak power handling. This is our most popular performance build because it solves the problem that kills more stock transmissions than anything else: heat from heavy towing.
For tuned daily drivers running 500 to 800 horsepower. Full valve body upgrade, triple-disc billet converter, expanded clutch packs with competition friction material, billet input shaft, and comprehensive cooling package. Built to handle aggressive driving and moderate towing without sacrificing daily drivability.
For sled pull trucks, drag trucks, and builds exceeding 800 horsepower. Full billet valve body, triple-disc billet converter with custom stall speed, billet input and output shafts, maximum clutch pack capacity with the highest-rated friction material available, and dedicated cooling system. Engineered for peak power delivery with the understanding that shift feel takes a back seat to holding capacity.
If you tow regularly at or near your truck’s rated capacity, a towing performance build will outlast a stock-spec rebuild significantly. You do not need a 1,000 horsepower build to benefit from performance components. A billet converter, upgraded clutch packs, and a valve body recalibration are the three upgrades that make the biggest difference for towing reliability, and they are available at a fraction of the cost of a full competition build.
Our towing and street performance builds are designed to be completely livable as daily drivers. Shifts are firmer than stock but not harsh. The converter locks up smoothly and runs cooler. You will notice the improvement most when towing or accelerating — the transmission holds gears confidently instead of slipping or hunting. Competition builds are firmer by design and are intended for trucks that see regular track or pull use.
Towing performance builds typically range from $4,000 to $7,000 depending on the transmission model and upgrades selected. Street performance builds run $6,000 to $10,000. Full competition builds with billet internals throughout can run $10,000 to $15,000 or more. We offer financing on all build levels.
Yes. We accept transmissions shipped to our Fort Worth shop from anywhere in the country. We build the unit to your specifications and ship it back ready to install. Call us to discuss your application and we will recommend the right build level for your power goals.
Every performance build comes with our 3-year warranty. We stand behind the components and the workmanship regardless of power level. The warranty covers defects in parts and labor performed by our shop.
Call Top Notch Transmissions today at (817) 386-7592 to discuss your build, or request a free estimate. Whether you are pulling a loaded gooseneck, running the drag strip, or building the ultimate street truck, we have the experience and the components to do it right.