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[Anonymous]

Been looking into lifting the XJ and want some thoughts on this.
The main reason you get vibes off a lifted xj (post 1997 mk2) is due to the slip yolk moving back on the output shaft (1in on a 2.5in lift) and giving enough play in the front UJ to cause vibes (the prop wobbles on the output shaft). Now then, if you lift with new springs the axle moves down from the body and away from the transfer case as the axle sits in the same place relative to the chassis and the wheelbase stays the same. Now if you lift with longer shackles the axle moves forward due to the distance from the front spring mount and axle not changing and the axle hingeing forwards, this in turn moves the propshaft forward along the output shaft.

So what I was going to do was test the above by undoing the rear shackles and jacking up the body to see how much the prop moves forward on the TC output shaft with a 2in shackle lift, wondering if I put a mix of lifted springs and longer shackles I can get the prop to sit in the correct position on the TC case (may need to use degree shims on the axle though to get either end of the prop to run parallel)

Bollocks or not?

[chrisjones]

Not sure.  Seems like an intrestin, idea, I'm sure there would be a few people who would want to know the outcome of your experiment. Me included.

Keep us posted.

[JamesH]

Theory seems sensible, would be keen to know the outcome of any practical tests.

Just to check ideas you mentioned. For a non double-cardan driveshaft, ie. stock XJ one, the output and diff lines should be parallel. Shackles will tilt axle end up, so will you be putting degree shims in backwards to normal to tilt down again. (I believe they are normally used to tilt pinion up to an output when using a double-cardan shaft)

I have only slight vibes at 40mph under hard ( ) acceleration so haven't done anything to mine with 3" rear lift.

[chrisjones]

I think the bigger problem is the extreme angle on the UJs when you fit a lift.  They don't do large angles and start to bind.  That's why trans. case drop kits work.  Double cardon joints mean the input and output shafts don't need to be parallel.

I think.

[Anonymous]

aint that bad on an XJ with less than 6" of lift, the prop is long enough not to make big changes on the UJ, I think the UJ design was changed for the Mk2, earlier ones had problems with the knuckles touching on 3-4" lifts and had to be ground down.

[Anonymous]

Aint got any probs with mine......but then mine is an OLD one as Steve keeps reminding me!!!  :lol:

[monkeybiz]

already done it m8, my xj had a 4.5" lift. 3" spring and 1.5" shackles and the shackles near enough poped the driveshaft to its natural position. i had no vibes at all at any speed so id say your idea is spot on.






BDS plug, this is how BDS achieve heights above 4" on yj's and xj's

[Anonymous]

good-o thats the same lift I was going for  

[chrisjones]

Let me know how it goes Steve.

[Mike Pavelin]

I have lift springs and shackles. no degree shims, TJ front yoke. No vibes or nasties.