Discovery to Defender gearbox conversion

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Dr_evil

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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 :mad:

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 :D

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.


26643d1322063767-whats-differende-between-defender-r380-gearbox-disco-one-adaptor.jpg



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



94829883-1025-4256-B169-41678B65237E-7008-0000076B3BB3EE8E_zpse4715dba.jpg

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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

discodefadaptor_zps28769447.jpg

discodefadaptor1_zpsd2a30cfa.jpg

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

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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



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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)

P1020488.jpg


P1020489.jpg
 
That's all looking quite involved Doc ;)

have you ever considered a career as an Engineer? :p


seriously it's looking good
 
Cheers :) just trying to help haha, James put me onto it but it was a bit hidden so that's everything consolidated as it were ;)

Will update once I bore it out and put the lt77 top on next weekend (hopefully)
 
Started making a new one today due to a slight cock up on my part with measurements…….


anyway its more or less done minus the 5/8th hole and two M10 grub screw holes


However looks like ashcroft sell the same conversion kit that I'm making

Ashcroft Transmissions - Selector Rail Adapter & Yolk

Yet again though for the cost I'd rather make the one up on the lathe than buy from them given that mine comes in at a 7th of their price and will look just as good, managed to get on a good lathe with a proper tool today freshly ground and its looking good

Will order up FTC5120 in the morning and hopefully it'll be here for the afternoon! If not may be next week before I get to change the selector over if the LT77 one wont fit
 
Pics as promised. Didn't have a flat bottom 5/8th drill so there's a slight hole in the centre but doesn't affect the fit. Bolts cut to fit but will replace the quadrant one with a grub as it needs to be one to fit the hole



Pics are in lower post now with precise measurements!



You will need a dividing head to do this properly or if not then some clever bodging with a 360* protractor ;) I went with the dividing head method
 
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No, be more like 1" I reckon given the spacing of the holes but the piece is 2" long and its easier to say :p

I'm hoping those pics I copied were accurate though as thats where I've drilled the holes so will find out when the quadrant lands

Will find out and update again once I have it, if anyone wants the measurements they're up there anyway
 
I've got a finalised adaptor piece and will be updating at the weekend to prove that it fits ;)

Turns out the measurements given were slightly inaccurate! So ignore the first post measurements and I shall get out the vernier height gauge tomorrow and make up some proper ones
 
looking good doc pity the bastard sold you a disco box, PITA to sort it by the looks of it

Proper arse of a job and £104 more down the drain :doh: still cheaper than a fender spec box though and was still a rebuild

either way its getting done now :)


Once this is sorted I think I'll drop the rear tub on and begin to assemble the bodywork again

Got my strengthening brackets for the seatbox since I removed the bulkhead and will be getting a few more cutting discs to finish off the bulkhead position swap :p its getting there slowly!
 
Proper arse of a job and £104 more down the drain :doh: still cheaper than a fender spec box though and was still a rebuild

either way its getting done now :)


Once this is sorted I think I'll drop the rear tub on and begin to assemble the bodywork again

Got my strengthening brackets for the seatbox since I removed the bulkhead and will be getting a few more cutting discs to finish off the bulkhead position swap :p its getting there slowly!
lol im saving gearboxes to trade in .....
 
Proper arse of a job and £104 more down the drain :doh: still cheaper than a fender spec box though and was still a rebuild

either way its getting done now :)


Once this is sorted I think I'll drop the rear tub on and begin to assemble the bodywork again

Got my strengthening brackets for the seatbox since I removed the bulkhead and will be getting a few more cutting discs to finish off the bulkhead position swap :p its getting there slowly!

had this with our old mk3 transit it had the old type 9 box,used to eat reverse gear could not get one they were like rocking horse ****e,in the end utilised a mt75 later box by cutting and plating the cab floor,but in the transit it was just tidy up with a newer gaiter,also took a type 9 out of a sierra and put the transit linkage onto that,PITA as well and reverse gear still jumped out after a bit
 
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