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Discussion Starter · #1 ·
Well I think that when you buy used parts it might be a good deal but now I don't think so. After changing my gears to 3:55-1 from 2:79 -1 with a change of a 3rd member it seems that I have a vibration through my drive train. Never had this issue before and the guy that I bought the 3rd member with new gears etc said it may make noise. Noise isn't the issue. Can having a gear set not adjusted properly send a vibration through the drive train . Never noticed the shifter handle shaking with the old gears now I can feel it. I am going to pull the 3rd member and put the old one back in. I knew I should have gotten it checked by a shop before I put it in.



Greg
 

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So the same thing happened to me when I bought a used 3rd member (it was actually rebuilt by a shop and never installed in the car.) Anyway I went from a 2.73 to a 3.73 track-loc and had pretty bad vibrations above 30 mph.

Long story short, I didn't have the drive shaft centered. So take a look at that u-joint before you go and pull the third member. I centered mine up and the problem went away.
 

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+1. I would not pull the 3rd member out yet. It's pretty hard to get vibrations out of one unless the pinion is bent. Although that's rare, it can be done if dropped just right. So, I'd agree that generally it's a U-joint issue, either cocked, a burr hanging it up, dirt in the saddle, or other related joint problem. Before pulling it apart, examine it closely to see if there is any misalignment or one of the caps not fully seated into the saddle. While straps are hard to mess-up, it's possible to over-tighten the U-bolt style retainers, binding the bearings. Be sure to torque properly. Slowly rotate the shaft to look for bends in the shaft, pinion, or general wonkiness. Finally, if it all looks good, pull the shaft from the rear, rotate it 180° and re-install to test again. Oddly enough, that often solves many driveline vibration issues.

David
 

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Discussion Starter · #5 ·
Might be time to just change the universal joints and start off fresh. And thanks for that info. Dennis told me to rotate the shaft and it wasn't the issue . Now I am wondering if at one time I did over tighten the universals




Greg
 
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