they came in the automatic 8s that have a lower redline. idk if its designed for those rpms

i have a used ds if ya need one

 

Most people fail to realize that due to the PPF the driveshaft essentially only rotates in a near straight line. Unlike a live rear end where the driveshaft moves at the U-joints as the rear end moves up/down with the rear suspension. The u-joint complaint here is essentially irrelevant with a PPF chassis setup. The u-joints only take up whatever very small misalignment might occur btween the trans tailhousing and differential. Within that context in never operates in the "gritty" range. The limited movement over time is what actually results in it feeling that way when you try to operate the u-joint outside of that small window.

 

I installed the lighter Mazdatrix AL driveshaft two years ago. Tracking it hard since then, spending lots of time in the upper RPM range in fourth and fifth gears. (Max about 7800 in fifth.)
No problems to report.

 

Ok, I’m in my original CF driveshaft from Dec, 2004 build date.

No problems to report here either.