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.
The first step of the process...
The first step of the process was to get pressure readings on the OEM transmission. To do this the DTT technicians installed a pressure gauge on the front servo port and took the truck for a drive. These measurements tell you where leaks are, as well as what problems might exist within the valvebody.
Bill's right-hand men Darrin...
Bill's right-hand men Darrin Eby and Vinnie Parray got right to it and started by detailing how this truck is used.
With the transmission removed,...
With the transmission removed, the teardown process began. The dark color of the ATF suggests high amounts of metallic material were present. The DTT technician suggested that this trans had about 5,000 miles left before total failure. One look at the magnet inside the pan indicates how much damage had occurred.
With the pan off and the filter...
With the pan off and the filter removed, a special tool was attached to the valvebody to bench-test the internal components for leakage. Next, the overdrive unit was removed. This back half of the transmission contains a heavy spring under 800 pounds of pressure. Careful, here-improper handling of this unit can cause serious injury.
These are the third-gear clutch...
These are the third-gear clutch discs, heavily damaged by slippage. Noticed the discoloration on the discs near the technician's hand.
This crud you see on the reverse...
This crud you see on the reverse servo is what floats around in the ATF and ruins transmission seals. It comes from the material on the friction bands as they wear. The only way to remove this substance is to change the ATF regularly.
With all the components removed...
With all the components removed and cleaned, a close inspection revealed tiny hairline scratches in the second-gear release servo that allowed pressurized ATF to leak past old seals, causing pressure loss, the primary cause of transmission slippage. Leaks like these prevent ATF from getting to the cooler and filter, as well.
To prevent leaks like these,...
To prevent leaks like these, DTT created its own servo that uses this special bushing that eliminates leaks caused by friction.
DTT goes to great lengths...
DTT goes to great lengths to ensure the quality of its components. The stock input shaft is in the background, the DTT improved design is in front. The billet input shafts and hubs were designed for heavy loads and extreme power applications. DTT says these shafts hold up to 800 hp and 1,600 lb-ft of torque.