47RE transmission upgrade.
Say hello to the Baja B.O.M.B.er, the latest addition to an extensive family of project vehicles here at Four Wheeler. The Baja B.O.M.B.er is a '99 Dodge Ram 31/44-ton 4x4 truck that we plan to turn into a desert-pounding chase truck. For those of you who don't know about Baja and the type of punishment chase trucks are subjected to, listen up: Baja is one of the harshest 'wheeling environments on earth. So follow along as we address the weak links and the high potential of the Cummins-powered Dodge Ram so that it can survive in Baja, and reveal some of the best-kept secrets of diesel-engine tuning and chassis-performance upgrades.
The automatic transmissions of Dodge Ram trucks are regarded as the weakest link in an otherwise stout drivetrain, compromised by poor electrical components and an inadequate lubrication system. With 50,000 miles on it, the 47RE trans behind the torque-heavy Cummins turbodiesel in the B.O.M.B.er began, during upshifts, to hunt for the proper gear. Shortly thereafter, the indecisive slush box would randomly upshift. Clearly, it needed help.
For that help, we turned to the experts at Diesel Transmission Technology (DTT) of Abbotsford, British Columbia, Canada. Owner Bill Kondolay has been developing solutions to premature transmission failures for more than 20 years. Bill takes pride in his company's success in producing transmissions that are built for longevity and driveability. Many of the innovations that make a DTT 47RE the Rolex watch of automatics come from Bill's continued involvement in NHRA drag racing. It's this involvement that provides Bill with the access to the materials and services that make his products unique.
One of the problems with this transmission is that the internal components of the 47RE were engineered with a gas engine in mind. A gas engine makes power at higher rpm than a diesel does. This becomes problematic because the efficiency of the oil pump moving vital ATF through the various components of the system is directly related to engine rpm. This pump must supply specific pressures for everything to work properly. A higher pump speed means higher ATF volumes. In a gas-powered Dodge truck you'll find the close cousin of the 47RE, the 46RE.
Just as its counterpart does, it has a pressure regulator valve that prevents excessive flow and ATF pressures from exceeding specific limits, which a high-revving gas engine is quite capable of producing. On the 47RE, the flow volumes are much lower, due to the lower revs of the diesel engine. Unfortunately, these lower volumes make a 47RE run very close to its minimum-pressure requirements. This means that as your transmission breaks in, and dozens of tiny leaks are created around seal surfaces, the essential pressure drops below minimum requirements. Follow along as we learn how to correct these problems to make a reliable 47RE.
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