BAD shake/vibration after diff change

[Lawry]

Hey guys

just swapped my rear diff in my 2003 d22 with a h233b 4.6 ratio.
also put another tail shaft in from a 1997 navara which is required.

however now im getting a very Vilolent shake/vibration when underload.
most noticable whem i take off hard in 1st 2nd or under heavy load in low revs.

the rear diff is an LSD which seemed nice and tight.
the U-bolts are torqued to 120nm not sure if they need more.

however my suspicions lie with the tail shaft.
would a severely worn uni joint or two do this?
or the centre bearing.
i was think bent tail shaft however is DOESN'T do it while coasting only under load.

thoughts???

anyone have a good condition tail shaft out of a QD32 varient navara.

cheers

 

[dilmah]

Maybe the shaft needs balancing?

 

[Lawry]

I just shook the center bearing and it clicks, has a decent amount of movement as well.

im going to pop out the uni joint and press on another centre bearing, i suspect the bearing has collapsed/

 

[fourocker]

Two pieces of drive shaft out of phase ? Or backlash in uni joints (shouldn't have any).

 

[Lawry]

yer i didnt take note of the of how they are alined. I suspect they may only be out of balace but thats not the vibration. inspected the centre bearing and it moves over an inch so its flogged!!!!

going to source one out on monday!
uni joints are nice and tight, no movement.

 

[fourocker]

Yeah center bearing should flex but not move easily, especially not an inch, there's been threads recently on center bearing issues and it seems some replacements are not up to the task.