[Ronw435]

I have the same problem, never really noticed a vibration except for a slight vibration coming and going like pulsing. Changed to 3.73 gears on the series 3 carrier with the thick gears from Richmond. I used the pro gear set. replaced the bearings set preload and backlash. preload was around 22 inch pounds on the pinion without the ring gear installed. Specs called for 25 so figured 22 would be fine. Set backlash to .008, specs called for 7-9. Ran for about 125 miles doing the break in as instructed. First 15-20 miles pinion was running around 160 degrees. Let cool down and took it for another 15-20 miles came back measure temp and it was down to around 140 with laser temp gun. Let sit over night and ran another 30 miles this time got home and temp was around 120. Problem I am having is a vibration comes in around 55 getting pregressively worse the faster you go. Had a new drive shaft put in about 1000 miles ago. Have rotated the driveshaft 180 degrees and vibration is still there. I read where someone said to rotate 90 degrees each time. Not sure you can do that with one piece ds. It does make sense that it is worse now as the shaft is turning faster. Went from 3.07 to 3.73. Gear wear pattern after 150 miles looks great. I guess maybe I should take the driveshaft out and get it "re-balanced" again? Could the spider gears cause this. When they fell out I might not have gotten them back with the same washers as it all fell out on the floor. Gears are not making any noise at all. The vibration gets worse when I push the clutch in and coast.

Any ideas?

Thanks
Ron