Howling/vibrations after 4" suspension lift

Hi guys, I've got a 2007 1.3 VVT Jimny. I've just fitted a 4" suspension lift with castor corrected arms all round, adjustable panhard rods and front prop spacer.

The axles 'look' to be centered and i still need to do the tracking. I'm running 205/75/15 tyres on 15x7 rims with the plan to fit 31's soon.

My problem is, when driving an aggressive vibration through the whole car can now be felt. It sounds like a howl and gets louder the faster I go. It feels like it's coming from the center of the car going back towards the rear.

It seems to be matched to road speed and not engine speed, if I push the clutch in at 30mph to drop the revs the noise and vibes are still there.

I've removed the rear prop and tried driving around on the front two and it became a lot less noticeable, in fact it felt like it disappeared. Put the prop back on and the vibes and noise come back.

If the axle is off center, even slightly, could it cause this?

I've read in another thread where the OP had a similar problem. They had to fit a rear prop spacer as well to cure it. For an 07 Jimny do you think a rear prop spacer is needed for a 4" lift?

Many thanks

Whilst i'm trying to figure this out, would any harm come to driving around with the rear prop off in 4WD using the front?

Have you still got the original transfer box and prop fitted then?...

I'm not sure, but I wouldn't have thought a standard rear prop (with the CV thing on the t-box end) would cope with a 4" lift?...

It's too short and probably right at the limits of extension and about to pop out.

Use an SJ series front prop on the rear if I remember right.

Yes the original Jimny transfer box and props are still fitted. Thanks, I'll keep a look out for an SJ front prop, I believe they are rare though.

Would a spacer on the diff end of the prop be enough?

You could always get one made, that's what I did when I did a 4" lift.

www.baileymorris.co.uk/en/4x4-extreme-land-rover

EDIT | Install - sj410.co.uk/charger/garage/100412.html