Discovery to Defender gearbox conversion

Dr_evil said:

Right, I got a discovery box cos the seller lied and basically was an arse about it when I tried to get some cash back out of him………


£250 for a new V8 bellhousing and AW transmission recon R380 box but should have been defender spec instead of disco the bastard

Anyway, onwards! (design and pics for the completed one courtesy of defcrazy)

This thread popped up http://www.landyzone.co.uk/lz/f6/discovery-engine-gear-box-ex-mod-s3-217336.html and after a few posts James mentioned a mod that would allow for a discovery box to be converted to defender spec without taking the thing apart to fit, the conventional way is to take FTC4588, FTC5120 and a defender selector housing then replace the disco bits. However in an attempt to not split the box James linked me to this thread

http://www.landyzone.co.uk/lz/f7/wh...n-defender-r380-gearbox-disco-one-137436.html

The following is a discovery to defender gearbox convertor, simple enough if you have a lathe or know someone with one. This is it about 50% complete so far, two of the three lips are turned and then it needs a hole drilling and tapping along with a 5/8th hole in either end with a 3/4" solid in the to separate them.

This adaptor started life as a 50mm bar and was then turned to the correct diameter

The piece will finish life looking like this (may surface finish it on the grinder so its super smooth) But essentially its a 2" long piece that makes up the lost selector shaft difference

You can see exactly why you need to move the selector back from this pic

This only applies if you're doing this mod on a series, if its a disco into a defender it should be fine distance wise.

Now as I've got a V8 fitted and the mounts are in the same place as the original engine and I'm using a modern box I had to do the following;

New crossmember made up for the middle where I have to chop out the old box in order for the LT230 to fit in.
IIRC is 120x100x5mm box and then I used 6mm plate for the ends, simple enough, chop the box 12mm too small then the 6mm plate makes up the difference

So why not just buy a defender box and save the hassle ?

Well a discovery box is peanuts compared, usually come with a decent engine connected and they're easy to come by!

This mod will then cost you £10 in steel at best and some man hours, compared to about £100 in LR parts, you'll need an LT77 or R380 top housing, but you can use your old one, an LT95 one could be made to fit I reckon. Going to get my hands on one and measure up.

Will also be doing another mod at some point which involves less box stripping


Heres the above mod in place (and yes it has worked, not mine but minimole's)

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Dr_evil said:

they were on here, if you cant make it yourself odds are your machine shop wont be any cheaper than ashcrofts

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Mythosez said:

i dont get why the def r380 Quadrant wont work in an lt77... the DISCOVERY lt77 box Looks the same like the def r380 from the inner where the Quadrant is locatet. maybe the r380 Quadrant will collise somewhere because of the reverse gear lock (i dont know) but even if this Comes true the r380 quadran can be modified i would say...

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