You should have the output hub/ring gear assembled onto the output shaft, and the rear planet installed into the rear ring gear before dropping the assembly into the case. The 350 is easiest to build if you load it all from the trans in an upright position. You can stand the case up on an inverted 5 gallon bucket with a hole cut for the output shaft, or inprovise another support system to load it this way. Once the output shaft and planet are in place you can load the steels and clutches, steel first, then clutch till the last clutch is in place. Then take your anti clunck spring and paste it into the case with petroleum jelly and install the fully assembled low sprag and housing into the case, you will have to twist the inner sprag race to line up with the lugs on the rear planet as these two go together. Once the support is in place in the case you can install the large snap ring into the case groove that holds it all in place and proceed with the remainder of the build. Sunshell next, then planet, then front ring gear and hub, then small snap ring on front planet to output shaft. Assemble direct drum and forward drum packs then put both drums together and load them into the case at the same time twisting the input shaft as you set the drums in so that the forard clutches engage the splines on the input ring gear. Once the drums are all the way down you should be able to lift them up an eighth inch and set them down and feel a very solid thud, if not, keep twisting till the clutches are all in position and the forward drum is sitting on the thrust washer on the forward hub. Next, drop the band into place, the intermediate clutches and then the pump assembly. You can establish final endplay by installing the pump without the pump o-ring and only a couple of pump to case bolts. Use a small punch inserted into the feed hole on the side of the protruding input shaft and pull up on the shaft. It should be about .025 to .035 total for best results. You can use thin steel shims behind the pump stator bearing to tighten it up if need be. These are available from your parts supplier. Have fun!
