Application: All Porsche® 928s with Automatic Transmissions Only
The Problem: Porsche® 928s equipped with automatic transmissions are prone to Thrust Bearing Failure (TBF) in the engine due to driveshaft creep. When TBF occurs, the damage to the engine is sudden and severe, almost always inflicting irreparable damage to the motor. Thrust Bearing Failure can occur on any automatic-equipped 928, and especially those on in performance-driven 928s.
The Mode of Failure: The OEM Porsche® 928 drive shaft clamp is capable of resisting 1700 to 2400 pounds of pulling force on the driveshaft before the driveshaft will move. During hard accelerations with good tire hookup, the drive shaft will twist somewhat as a normal part of operation. The twisting of the driveshaft also shortens it. This, and the mechanical property known as "jerk" is enough to yank the driveshaft out of the Porsche® OEM clamp in increments. But, when the driver is off the throttle and the driveshaft untwists and returns to its former length, it is not allowed to get back in to the clamp. The result is a driveshaft that slowly gets "longer" until it pushes forward on the crankshaft with enough force to wear into the crankshaft thrust bearing. The final moments are when the thrust bearing gets hooked by one of the rotating crank counterweights and starts to spin in the block. Complete engine failure is only seconds away at that point.
The Solution: Our Super-Duty Driveshaft Clamp has been tested and shown to withstand over 4,800 pounds of pulling force! The driveshaft will twist as before (as designed) but it will not be able to creep out of the clamp. Therefore all the gaps and pressures in the torque tube/flex plate system of your 928 automatic will remain as specified, and TBF has been stopped. This product tested in the field now for 4 years.
928 Motorsports Quality: Expertly machined from high-grade steel billet. All hardware included, as well as detailed installation instructions.