The introduction of the Allison 1000 transmission to the diesel truck market restored confidence in consumers that an automatic transmission can indeed handle the demands of exhaust braking without any electronic addition. But while the Allison is suitable for stock applications, we've found that it does have its limitations particularly when flywheel horsepower exceeds 370 horsepower. That's when the stock clutch packs can begin to slip, putting the computer in the dreaded limp home mode and once a clutch has slipped, the next time it will slip easier and easier. At BD, we make several modifications to the Allison to meet the demands of high-performance and heavy-duty usage. A new convertor lock up valve, updated lube & regulator and pressure release spring has been installed. With either the C1 or C2 clutches being engaged in all gears, this creates a weak link in the transmission. We designed 20% more friction surface and use high energy clutch material. We have also added extra frictions in the remaining clutches to improve holding capacity. We have modified power pistons hydraulics and return springs are changed while main line oil pressure is raised to increase clamping force on the clutch packs. If you've modified, or plan to modify your Duramax, the first step should be a BD Allison transmission. Call us today! We also offer Build-it transmission rebuild kits with our modified parts for those that want to build their own performance transmissions. New for 2010 we now have available exchange units for behind the Duramax LMM engine.