PROTECT THAT RAM
BD DIESEL’S PROTECT68 TRANSMISSION KIT
AThe Cummins powerplant was a homerun for Dodge clear back in the late ’80s, when they first introduced it into their light duty truck lineup. That first-generation 12V motor didn’t make much power by today’s standards, but it was a reliable engine with lots of potential. As the years went on, the 5.9L Cummins engine just got better and better. The P7100 injection pump in 1994, introduction of electronic control in 1998, the switch to common-rail fuel injection in 2003, and then the major jump to an all-new, 6.7-liter, emissions-compliant version in 2007. The Dodge Cummins is nearing its 30th year of unity, and yet most Dodge Ram owners will agree the “weak link” has always been the automatic transmission.
Obviously, in those 30 years Dodge has made revisions and changes to the automatic transmission backing the Cummins powerplant, but it always seemed to be a little too late with each. In stock form, they haven’t held up like the Ford or GM transmissions. That said, the 47RH and 48RE once built up with a host of aftermarket parts can handle just about anything the performance market has thrown at them, including 2,000+ horsepower and 8-second quarter mile drag times. In 2007.5 the 6.7L Cummins trucks came with an all new six-speed transmission dubbed the 68RFE. The new transmission was beefier than the previous years, and the extra gears offered better ratios for improved drivability and more overdrive for increased fuel economy. At factory power levels it seemed to work quite well too, but as the mileage increases and even just a little extra power is added, they start to show their signs of weakness.
Just about every owner taking the time to read this magazine has probably had interest or already added a performance chip to their 2007.5+ 6.7L Cummins. The added benefits from better throttle response, quicker spool-up, maybe some mileage increases, and the extra torque for towing make it hard to resist. But from what the market has discovered, past that 450hp level the transmission and TCM tuning is going to start getting angry about life. To help improve the overall longevity and performance from the 68RFE, the engineers at BD Diesel developed their Protect68 kit, which can be easily installed to increase transmission line pressure while reducing internal valve body cross leakage known to be a common issue.
Like any automatic transmission, fluid line pressure is used to apply force to the clutches to create holding capacity within each gear,
and by increasing line pressure you can reduce clutch slippage and help transfer power more effectively. Unfortunately, it’s been found that the valve bodies in the 68RFE have a serious issue with internal cross leakage, meaning fluid can travel where it shouldn’t, at the wrong time, creating pressure inside the transmission where it doesn’t belong. This can lead to premature wear and fault codes, reducing the lifespan of the transmission. These are issues at the factory 160psi line pressure, so you can only imagine how it gets when additional line pressure is requested in tuning.
The P0871 DTC fault code commonly thrown by this transmission is from the overdrive circuit seeing pressure when it shouldn’t. At 16 psi within the overdrive circuit it’ll begin to apply the overdrive clutches. Whether it’s asking for overdrive or not, at 16 psi it’ll mechanically engage overdrive. The internal cross leaks due to poor mating surfaces of the valve body pieces can feed 11+ pounds of pressure into the circuit and start causing a dragging effect on the clutch faces. This will obviously create unwanted heat and wear, leading to premature transmission failure.
The Protect68 kit includes everything needed to not only fix these internal cross leaks, but also increase line pressure to as much