O.K. This vibration was here before I did the motor and tranny work. I bought the car back in November and it did it then. However there were some other problems the car had and I concentrated on that stuff first. The car has always done this since I bought it. And I thought wheels and tires also but I sold the ones that came with the car when I bought it and got new ones. It still does it. This is what I have replaced and done and to no prevail still vibration. rear shocks and springs, front shocks and springs the shocks and springs are just OEM replacements. Tie rod ends , ball joints, steering rack, power steering pump, lower end of motor rebuilt, tranny rebuilt to incluse 3 of the actual gears, Aluminum driveshaft was balanced and U joints were said to be good. The car had a 5 lug swap done to it before I bought it. I know the front spindles are off a 94 not sure how they did the rear but I measured the rear one time and if I recall right from hub to hub it was something like 61 1/2 or 62 inches. The list of mods I had for this car claims the axle to be 28 spline 4.10 gear. Dont know if its normal when I was pulling the drive shaft out to pull the tranny the nflange on the driveshaft that bolts up to the rear when I removed it there was some fluid that dripped out from back there at the rear end. But thats that.