did a rear end change to go from stock gears to 373's and have noticed a vibration from the rear only when reaching speeds of 120 kph. google search seems to say this is common with gear change. Don't think its tires or rims as I changed to a different set of rims and tires and no change, universal joint has no play and driveshaft bolts are tightened and loctited. So i think I narrowed it down to drive shaft, do I switch to aluminum or if anyone else that has experienced this how did you solve it? It's a 1988 with 8.8.