Comments for what their worth;
- I worked in the auto parts industry for many years and was an amature drag-racer and car collector. Upon installing new 4. 56 gears in my brother's 427 solid lifter drag car, I instantly sheared the factory (greasable) U-joint in half. Replaced it and sheared the new one as well. Went to the store and grabbed a TRW u-joint and it held up until he sold the car. The TRW u-joint was solid (not cross drilled).
- I am sure that the reason that DC is using the sealed u-joints has more to do with the torque of the Cummins than it does with saving a grease fitting.
- Not to be rude, but would you rather replace a worn out u-joint or have your driveshaft laying on the pavement because it couldn't take 500 ft lbs of torque? DC doesn't build the U-joints, thier engineers just specify what they want. Personally, I have allways considered U-joints to be consumeable parts much like brake pads, belts & hoses and clutches. If my U-joints last for 50,000 mi or more, I'll be happy.
Cheers
Dave