Reinstalling rear driveshaft question (long)

I'm dumb. I recently pulled the rear shaft due to vibes, and forgot to mark the position on the yoke and flange. I've searched and found a little info on phasing of the u-joints. I have the RE hack-n-tap, with a cv driveshaft. Is it possible I've reinstalled it incorrectly (out of phase)?

If it is installed incorrectly, this is my thought - leave the pinion u-joint alone, and turn the shaft by one stud on the t-case flange and see if the vibes go away...repeat as necessary. Do I also need to try changing the pinion joint position as well? Or is this setup immune to "phasing-install" problems and I need to look at other possibilities?

Background: I recently swapped the 8.25 for an XJ44. The pinion angle is currently 1.5* below the DS angle, so *should* be correct. I have vibes that exist above ~45mph, and only when I have my foot on the gas - coasting nearly eliminates the vibes. I have run it without the rear shaft and is completely smooth. I figured I'd ask about the phasing issue before I took the shaft into a driveline shop. There were no vibes immediately prior to the axle swap, so I don't *think* anything's wrong with the shaft or joints. If there's some completely different issue to check for, feel free to chime in. Thanks.

You cant alter the phasing unless you took the slip-yoke apart.Sometime rotating one end does help with balance issies.

RCP Phx said:

You cant alter the phasing unless you took the slip-JOINT apart.

Click to expand...

fixed...


still true

did you make sure the RE flange was tight on there?

The RE flange has been installed for a couple years now, never any issues with that. The slip in the shaft didn't come apart, so sounds like not a phasing issue. Maybe I'll try rotating the shaft position as per RCP's suggestion. Mostly looking for easy things to check or try before I start paying other people to track down the source of the vibes.

XJ_ranger said:

fixed...


still true

did you make sure the RE flange was tight on there?

Click to expand...

No need to fix it since I was already correct.
http://www.rockforddriveline.com/slipyokes.htm

dang I didnt even know this phasing business was an issue. any write ups/more info on this??

start with unbolting your DS from the pinion yoke and rotating it 180º.
check the condition of the u-joints.
if you pulled the slip appart then make sure you put it back together. Yoke ears welded on the shaft need to line up.

Are you guys saying that the rear driveshaft ( 2 pieces) the slip yoke and the the main shaft have an actual direction ? I have always taken it all apart (when changin u joints) and put it back together not loking at any marks or anything ? is this wrong ?

pete