Well, hopefully you can learn from my mistake. I bought a used fms aluminum driveshaft from a guy when I did my 3.73's. The car vibrated worse and worse as the speeds got higher(highway speed) Not only did the rear vibrate, it whined too. I finally took the rear cover off to see if something was loose in there. When I turned the carrier it would bind in one spot of a turn just like you describe. I figured that I installed them incorrectly, so I reset the gears and drove it for a while more. Same crap. Finally I blew the trac loc at the track, so I took the rear cover off again. The gears were still binding in one spot. The track was closed for the season, so I figured I would throw my 3.08s back in since the gears were obviously not right. The car still vibrated the same, and the gears started to whine just like the 373s(took the cover off and the 308s were now bent and binding in one spot. This spring I took everything apart, threw in 31spl moser axles, eaton posi, NEW 373's and put it all back together correctly. The gears spun freely with no bind, so I ran it easy for awhile, but I still had some vibration. The gears seemed ok, but within a few weeks the vibration became steadily worse. So I unbolted the driveshaft and found that the pinion was loose. I tightened the pinon and reset the gears, only to find that these 3.73's were now binding in one spot just like the others. Finally this week I decided to have my driveshaft checked. I got a call from the machine shop about 2 hrs later, the driveshaft was shot. The yokes were bent, and the ujoint caps were loose inside the yokes. Believe me, I thought the driveshaft was ok, but I dont have the test equipment the machine shop used, the shaft seemed ok and tight the whole time. I checked the ujoints a number of times, they were ok, the driveshaft was whipping back and forth on the ujoint caps causing the vibration(and bending the pinion). Moral of the story, used driveshafts and gears are like condoms, if YOU are the one that bought them then you know that they are good, otherwise dont trust them.
I not only wasted 100 bux on a junk shaft, I have a total of well over $1600 stuck in my rear end all because of one A$$hole, not to mention the time spent on the work(thank god I did it myself). So, after spending all this money on junk, I have to buy a new driveshaft, install kit and gears to replace my 3rd set of gears because someone pawned their crap off on me.
CHECK THE DRIVESHAFT!!!!!!!
Ted
