Thread: Uni's out of phase?

Knowing you, Knowing me, the flange planes on the front of a standard RRC are not parallel, let alone a lifted one. the diff points up to the t/c & the t/.c is level, which is stupid.

on a standard height Rangie the front shaft has to be 45 deg out of phase,

on a 3" lift you will need caster correction or a double cardin shaft

if your prop shaft is in phase first thing I'd do I do I do is make it 45deg out at least it will improve matters.

If it was fine before & only just started making the noise the UJ's may be flogged out, it might cost some money money money. Mama Mia whats with the Abba songs .

Fernando

This subject was discussed recently in the "Technical Chatter" forum - U Joint / Yoke phasing F & R prop shafts

I was unsure if mine were right when I pulled them out, but it turns out they are. 23 degrees out for the front, in phase for the rear.

Think you'll find 45 out of phase is correct for front shaft on RRC Disco & Defender

Originally Posted by Not_An_Abba_Fan

Just a small problem (maybe), my 1989 Classic has developed a grumbly noise just at the coasting point between acceleration and deceleration. Once the drive line is loaded up it doesn't make the noise. I have done a 3" suspension lift and was thinking the planes of the uni joints are no longer parallel. Would this make the noise? I can feel it through the floor as well, which leads me to believe that it is the problem.

Being an auto, I am hoping it isn't the torque converter.

There is the cause

After running at other heights the uni's will be bedded in at the older height.

The shafts now running at "unusual" angles so introducing noise..


However, as mentioned... At that lift you need to look at a DC shaft....

A CV shaft will also work. But may cost more and be harder to find than a double-double cardan shaft (double uni joints at each end).

how will castor correcting help the prop-shaft?

Originally Posted by uninformed

how will castor correcting help the prop-shaft?

Castor correction by offset bushes or corrected Radius Arms will turn the diff housing back to its original position so that the pinion flange angle is going to be back down to 6deg upward in the case of RRC Defer etc or back down to Horizontal for a properly designed 4x4

I have to disagree. Its original angle is in relation to the axle height/spring length. So if the front axle down travels through its arc (scribed by the RA's) the pinion angle changes through out. If you put longer springs in the pinion angle has changed, but true to its natural arc, which the LR engineers would have calculated to be acceptable, using prop-shaft length in relation to RA length.....

IMO you dont want to change castor at the housing, this only makes Prop-shaft angles worse. If you want to correct castor, do it at the swivel balls. If you are having Prop-shaft problems, a double carden may help. I have a defender with 2.5 inch lift, I run a disco 2 front prop. All that needed changing was the transfer case output flange.