BMW N57 8hp to TD5 Auto adapter kit
	
	
		
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				Originally Posted by 
admiralranga
				 
			That's not what the vsb14's say, atleast in WA you can only do a manufacturer's alternative gearbox as a basic inspection. Anything else requires certification
			
		
	 
 Victoria follows the same rules.  Changing the gearbox to something that was not offered as an option needs modification approval.  Same applies to changes to rear diff ratio’s to something not offered as an option.
This is the relevant VSB:
https://www.infrastructure.gov.au/si...01Jan_2011.pdf
There is a checklist which shows getting engineering sign off should be fairly straightforward as there is nothing too onerous that needs to be complied with,  as long as you are not also modifying the engine at the same time to crank up the power output by more than 20%. 
It would be a nice mod!
	 
	
	
	
		BMW N57 8hp to TD5 Auto adapter kit
	
	
		Same story admiral - as soon as you fit an engine that was not an original option it is a modification that needs engineering approval.   The reason for this is there is no pre-existing ADR compliance approval for that combination.
But if just increasing the power of the original engine, then yes the 20% is from the highest HP engine that was offered as an option can also be approved (brake package must also match what came with the alternative optional engine).
So in theory, for the humble Td5 this means you can go to within 120% of the 4.6’s power output.
There is also a checklist for this as well in the engine section of VSB14.  
https://www.infrastructure.gov.au/si...jan2011_v3.pdf
All the sections can be found here:
Vehicle Standards Bulletin 14 (VSB 14) | Department of Infrastructure, Transport, Regional Development, Communications and the Arts
I personally wouldn’t be put off by getting engineering approval, and if doing something extreme but within the approved list of mods if this means getting an approved engineer to sign off that it is an approved modification, then this is probably a smart idea anyway - especially from an insurance point of view.