Originally Posted by Sieg (Post 551930)

Still fighting the driveline vibes issue!

Put the car on a drive on lift and checked angles.

Trans 2.2* down
Driveline 1.4* down
Pinion .6* down

According to this calculator I'm .15-.25* down on the pinion from 1 to 1 operating angles.

I double checked the u-joints and there's no noticeable play.

I finding it hard to believe .25* is causing a relatively noticeable vibe that comes in around 62 mph in 5th gear. (.80 OD)

I've been using .5" x 2.25" x 18 ga metal shims to add to the wedge until it's zero'd. One more adjustment and angle check and if that doesn't do it I'll take the driveline out and check it's balance.

The 3:73 gear has obviously compounded issues......IMO.

:bang:

Originally Posted by GregWeld (Post 551951)

It could have compounded an issue yes -- driveline speed would be higher.


My guess is --- it may have more to do with the output shaft of the tranny... and how much driveline is hanging out.

Originally Posted by Sieg (Post 551964)

The measurement from the seal (which is very close to the end of the shaft) to finished surface of the yoke is actually 29mm or 1-1/8" at ride height.

Originally Posted by Flash68 (Post 551969)

is that the measurement that is generally supposed to be approx 3/4"?

Originally Posted by Musclerodz (Post 551970)

is it a steady rpm vibration or power on or power off vibration.

Originally Posted by GregWeld (Post 551989)

3/4" is the spec --- and out 1 1/8th is a bunch. This doesn't mean that's your problem -- but sometimes it's a stack up of little errors.... too much stick out - a minor out of balance and boom - ya got a problem you can feel.

Since you've done just about everything else... it's time to look at "what else".

Originally Posted by Sieg (Post 551985)

I'm not sure what the spec is but that would be what I'd think is about right. Thankfully we have a longtime local driveline service.




Comes in steady at certain rpms and gears. Noticeable on decel, changed for the better with a passengers in the car. I've done so many shim adjustments I can't quote specific ranges anymore. :sieg: Hopefully I get a chance to drive it tonight and see if removing a .0375" (20 ga) shim made any difference.

Before the 3:73's were installed there was a slight but tolerable vibration in the 65-70 mph......rear view mirror was still usable. That's not the case now. :D

I'm guessing driveline balance may be off as Blake mentioned, but that yoke depth could be a contributor. When the car was on stands with the rear unsupported the yoke pulls out about 1/8" from the ride height position and there is some slop, at ride height the slop is reduced to what I "think" would insignificant........but thinking has got me in trouble more than once. :D

Originally Posted by Musclerodz (Post 551998)

If its noticeable on decel, roll the pinion down further. I just had to reset a ridetech 4 link that had a vibration on decel. I would roll it at least 1-1.5* down if you have not done that yet.