As above, garage is lost as to what the problem is, accelerate normaly then at around 2500rpm in 3rd engine will suddenly feel as if all power has gone and judders (similar feel to trying to set off in 5th???) change gear or accelerate hard, or let off and accelerate again it MAY go away, or might not, next time it may happen at 1500rpm, might not, it follows no pattern.

If you floor it from 0 it happens but hardly noticeable until you stop accelerating through the gear, say you sit at 70 in 6th it might start to judder.

completely lost

Ideas?

Check the condition of the vibration damper at the back of the propshaft in front of the Haldex/differential unit.  If you can move the outer metal mass forward and backward excessively or it doesn't return back to position, this may be the problem.

 

Tech