Norwood

[Sieg]

Originally Posted by GregWeld

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.

Funny you mention that because I measured how much yoke was left on the table today and was thinking the same thing.
Inland Empire supplied the shaft with the kit and I think they error on the short side. Ideally I'd like the shaft to be .3-.5" longer.

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.



As noted before you're the best guesser I know.

[Blake Foster]

We have found that the GOOD strange yokes can make a difference as well as the drive shaft balance. some shops only balance at about 800-1100 rpm and the drive shaft speed is a lot higher obviously. good luck it is like chasing your tail sometimes

[Flash68]

Originally Posted by Sieg

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.

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

[Musclerodz]

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

[Sieg]

Originally Posted by Flash68

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

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.

Originally Posted by Musclerodz

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

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. 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.

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.

[GregWeld]

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".

[GregWeld]

Originally Posted by GregWeld

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".

The cheap fix is to move the engine back....



Kills two birds with one stone...



Too much hanging out causes the driveline to "orbit".....

[Musclerodz]

Originally Posted by Sieg

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. 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.

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.

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.

[Sieg]

Originally Posted by Musclerodz

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.

Thanks, I've taken it past the best spot in both directions. After the last month I wish it was a 4 link!

I've done enough shimming to be pretty sure it's balance or the yoke penetration possibly.

The one change I did make to the previous setup was installing urethane bushings in the rear spring eyes (fronts were already in) I guess that in itself could have amplified a vibration condition but the difference was too drastic IMO.

Test drive window of opportunity is now!

[Musclerodz]

Originally Posted by Sieg

Thanks, I've taken it past the best spot in both directions. After the last month I wish it was a 4 link!

I've done enough shimming to be pretty sure it's balance or the yoke penetration possibly.

The one change I did make to the previous setup was installing urethane bushings in the rear spring eyes (fronts were already in) I guess that in itself could have amplified a vibration condition but the difference was too drastic IMO.

Test drive window of opportunity is now!

Didn't realize you were still on leafs. Have you considered changing to a 3" aluminum driveshaft? The larger aluminum shaft will absorb some vibrations that a small dia steel may amplfy.