Wanted to give an update:
So I took off my new rear driveshaft this weekend, thinking I was going to rotate the slip yoke 180 deg, just to see what would happen.
Much to my surprise, I noticed something new that I didn't catch when I was first installing it a few months ago. There are pink paint match marks on the shaft potentially(?) indicating how the slip yoke should be aligned. And even more to my surprise, they indicate that the shaft was balanced "out of phase" or aka "inverted phase." (You can see the 80 series guys talking about inverted phase here for their front shaft )
Just as a refresher, when I got the new shaft I took out the slip yoke to hand grease the splines. (I unfortunately didn't pay attention to the alignment before taking out the slip yoke to grease the splines.) When I put it back together I put it "in phase" with all three zerk fittings pointing in the same direction. I feel kind of like an idiot for not noticing these pink marks before. So I got kind of excited thinking this was my problem. So rotated the slip yoke 90 deg to line up the pink marks in the inverted phase and tried it.
Sadly it did not fix it.
I have only taken a quick drive, but the vibes are still there. Seems like the vibration pitch is a touch higher and peaks around 70mph now. But still pretty bad.
So now I'm a bit confused. I tried to find some other pictures of brand new shafts to see their orientation.
Anyway, on to next steps. I've got new rear sus upper arms coming this week. Going to try that first. And then if that doesn't work, will probably try swapping the slip yoke again 90 more deg to make it back in phase again the other direction.
Curious if anyone here has any advice on alignment here? Did your new shaft come with paint marks indicating an in phase or out of phase alignment?
Pink marks very similar to the white ones on my old shaft. Just out of phase:
So I took off my new rear driveshaft this weekend, thinking I was going to rotate the slip yoke 180 deg, just to see what would happen.
Much to my surprise, I noticed something new that I didn't catch when I was first installing it a few months ago. There are pink paint match marks on the shaft potentially(?) indicating how the slip yoke should be aligned. And even more to my surprise, they indicate that the shaft was balanced "out of phase" or aka "inverted phase." (You can see the 80 series guys talking about inverted phase here for their front shaft )
Just as a refresher, when I got the new shaft I took out the slip yoke to hand grease the splines. (I unfortunately didn't pay attention to the alignment before taking out the slip yoke to grease the splines.) When I put it back together I put it "in phase" with all three zerk fittings pointing in the same direction. I feel kind of like an idiot for not noticing these pink marks before. So I got kind of excited thinking this was my problem. So rotated the slip yoke 90 deg to line up the pink marks in the inverted phase and tried it.
Sadly it did not fix it.
So now I'm a bit confused. I tried to find some other pictures of brand new shafts to see their orientation.
- This one is just like the old one I had on before. In phase, with white paint marks instead of pink
- This one on partsouq also shows "in phase" alignment, but only shows one white paint mark. It also seems like all zerks are pointed the same direction for this alignment.
Anyway, on to next steps. I've got new rear sus upper arms coming this week. Going to try that first. And then if that doesn't work, will probably try swapping the slip yoke again 90 more deg to make it back in phase again the other direction.
Curious if anyone here has any advice on alignment here? Did your new shaft come with paint marks indicating an in phase or out of phase alignment?
Pink marks very similar to the white ones on my old shaft. Just out of phase: