Thread: Disco transfer box into a TD5 Defender

Originally Posted by nedflanders

Sorry if this has been covered but it was a fairly common mod in the UK to swop the defender T-box for a Disco one to improve highway travelling, has anyone done it and what are the benefits?
I realize reduce revs and noise but if you've done it was it worthwhile, would you recommend it and would you do it again, did it improve fuel economy?

I've done the install for a few and the consensus seems to be good if you don't tow or run larger rubber.

The tdi needs a little fuel pump massagery and I suspect the td5 would be ok up to about gvm and might support a small trailer without needing to be chipped up but you might want it just a little fatter in the low to mid rev range just to help it hold fifth a little better on hills and headwinds

The trouble is that this change changes all of your gearing. Might be a bit better on the highway but the rest of the time its a case of never having the right gear. I am speaking from experience with a 300tdi and it may well be a better fit with the td5.

In my case it put more strain on everything, ran higher egts and was a bit of a pig.

Better way to go IMO would be to use the V8s 5th gear ratio and leave the rest as it is. Best of both worlds. Ashcroft offer this option with their boxes.

You need to have a fairly significant tune to take advantage of the V8 fifth gear but it is an option worth considering.
Why not an overdrive unit? Few of those kicking about

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Not directly related to the OP question but if this mod was done, does it make any difference if the LT230 comes out of an auto or manual Disco ??. eg. Are auto/manual T/Cs the same ?

Google Ashcroft Transmissions ratio calculator
AM

mate did it to his tdi 110 and wouldnt go back, i did it to my 300tdi 110 about 150,000ks ago and wouldnt go back but mines an auto

Originally Posted by pop058

Not directly related to the OP question but if this mod was done, does it make any difference if the LT230 comes out of an auto or manual Disco ??. eg. Are auto/manual T/Cs the same ?

All the same.

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The idea was to make it better for highway, I tow a camper trailer and the idea was to have a more usable 4th as its the strongest gear. Im running a TD5 with a stage 3, boost box, big intercooler, decat, egr removed, centre box removed. Just want to drop the revs in 4th.