How's your driveline angles?

yeah they are within 2 degrees of eachother 

How's the diff?

Hi Kizzy,
The strange thing that it is only on deceleration.
 
Do you still have the problem in neutral and with the clutch in?
 
If it is not the gearbox and the problem is when you are not under load I would be looking at the diff and or the tailshaft. Had you used the same diff in the same car previously? What else has changed?
 
Clutches can also cause problems, although it doesn't sound like a clutch drama in this instance.
 
Cheers,
 
Damion

Thanks damion, 
 
As soon as you put the clutch in or put into nuetral, it goes away, it only happens when the engine is being driven by the diff, I have had the diff totally rebuilt as i was sure that was the issue but it is still the same,
the gearbox is facing down 3 degrees and the diff facing up 2 degrees (approx as gravity angle finder is not the most reliable.)
 
The tailshaft has been balanced twice and new unis were replaced before balancing.
 
I did the hilux diff conversion and gearbox at the same time but it wasn't doing it with standard mk2 diff and type 9 box