Installing a lightweight single piece driveshaft on the 240sx offers a few benefits over the factory 2 piece unit. First, your driveshaft is considered a rotating mass and as such, any weight saved on your driveshaft translates into a quicker, freer revving motor. This effect is similar to installing a lightweight flywheel on your car. Second, the single piece design of an aftermarket driveshaft means there will be less play in the shaft. With one less joint to go through, the single piece unit will give a more direct feel between the driver and the rear end, ultimately improving the cars feel and response.
Getting started (removing the factory 2 piece driveshaft)
First things first, if you don’t have access to a lift, place the car on jack stands. Next disconnect the front half of the driveshaft from the rear half by removing the 4 bolts at the center joint. (Engage the e-brake to make sure the driveshaft doesn’t spin) The rear half of the shaft will now swivel downwards and the end will rest on the floor. Now remove the bearing cover from the front half of the driveshaft by removing the 2 17mm bolts. Pull the front shaft towards the rear and it will slide out of the transmission. Finally, disconnect the rear shaft from the differential by once again removing 4 bolts. The factory driveshaft is now fully removed from the car.
The four bolts (index finger) and the bearing bracket (thumb).
The front half of the driveshaft removed with the rear swiveled downward.
The rear shaft connects to the differential via 4 bolts.
Installing the new driveshaft
Installing the new shaft takes only minutes. First, slide the front of the driveshaft back into the transmission. Slide it in a little more than necessary and then raise the rear side parallel to the rear differential connection and then pull the driveshaft backwards until the differential and shaft mate. Use the previously removed bolts to attach the new driveshaft and tighten them to 29-33 ft-lbs. Thats all there is to it.