Discovery to Defender gearbox conversion

MoorlandBOB said:

lol im saving gearboxes to trade in .....

Click to expand...

I've just been given an LT95 for the cost of a pint so that's my spare sorted!





Will look into getting a roverdrive for it at some point too

THEengineer said:

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

Click to expand...

Always fun making stuff fit

measurements taken, will upload later with description of the best way to turn it and mill

Right here's the accurate measurements and some pics


Its 43.5mm tall

5/8th shaft is 20mm long from and then a tapered mound below that or 3.3mm

The base is then 18.2mm tall

The hole in the centre of the base is 5/8th's or 15.87mm by 17.1mm deep

The two M10 x 1.5 grub screw holes are 4.1mm off the bottom of the base and then the hole on the shaft is 5mm from the top, these measurements are on the tap size and from the outermost edge of the hole not the centre.

The holes are offset at 65* from each other, should add that the hole on the shaft is not all the way through it is about 5mm deep and only has one turn of the tap due to the grub screw that fits in there having a tapered bottom

Width of the fat part is whatever you want it to be, I'd suggest 1 1/4" as it looks about right to me

You'll need to buy one grub screw as you can reuse the one from the disco box for the second

Heres the pics of how to do it anyway



Long bolt is from this hole




Short bolt holes








With those three removed then take off the cover plate to get access to number four







Remove the selector housing






Selector shaft exposed






5mm allen key and a suitable driver to get some purchase on there




Remove the screw





Other grub screw you'll need





This is the selector rail adaptor





Gear selector quadrant




You need to push the shaft into third in order to get enough space to remove the disco selector and get the defender selector mechanism on there





This is the old mechanism





Apply loctite to the screws




Pointed one goes onto the shaft that slides into the selector





Tighten this mutha####a up! And I mean tighten!





Long grub screw now








Apply loctite again




Again torque the bastard!





You don't want them coming undone!


Step back and take a break




Remove the LT77 selector from your chosen storage space







Apply a good bead of sealant and begin assembly







Locate it on dowel and remember where your bolts came from



Begin with the long bolt





After this just tighten the buggers up, I found out I cant select the bottom set of gears too easily which on inspection looks to be the bias plate that needs some fettling so I'll sort that at a later date but for now thats a how to do it with pics


Hope that helps anyone who may be considering the same thing

no 12 in your diagram plus remove rev plunger

Updated version (extra pic) and thanks, will have a go at it if I get a chance





Found the supposed problem according to Ashcroft and with some help from JM plus a lot of scouring of the parts manuals. I will confirm this tomorrow if I get a chance!


Theres a T piece that isn't needed within the LT77 selector housing if fitting it to the R380. The LT77 actually has 3 more pieces to it than the R380 mechanism

Anyway heres the pics



R380








And the LT77











Heres the T piece that may be the problem!

no 12 in your in your parts list r380 has one but its secured into the front of rear housing by one bolt ,reverse plunger needs removing too

Removed the plunger as R380 reverse switch is in the box as far as I can tell (thing on passenger side with two wires)


Will remove the housing and update, as said goes in PM it stays in gear if held so would assume that its just not fully engaging as that things blocking it



I'll whip off the top and re-seal with more gasket tomorrow if I get the chance if not I'll do it when I fit the transfer box next weekend, would have been a lot simpler had I found that post on Ashcrofts site before I fitted it together :doh:

thats the rev switch ,

Cool, will look at wiring that up then, cant be that hard haha

easy just needs a live feed in ,out to light

sweet, no need for relay in that case ?


if so will make up some wiring this week so its ready to plug in when I get the tub on and find a suitable LED bike light to use as a reverse light

no need or a relay

jamesmartin said:

no need or a relay

Click to expand...

Excellent


Well then I think that concludes the gearbox how to

youve done well ,

Thanks your help on the matter was great too!


Wouldn't have gone down this route if you hadn't pointed me towards that old thread

All works now, removed the T and the old extra reverse plunger that was in the back of the selector and all gears select just fine now

Resurrecting this thread if you don't mind. In the eight months or so since you installed this conversion, how is it working? Any pros or cons to using the discovery box in the defender? I ask as I'm about to fit a 300tdi to my 90 which came from a discovery with the discovery box. I also have a V8 R380 box that I was thinking about have rebuilt with the proper input shaft to fit this conversion as well. Any thoughts would be much appreciated.

Cheers,
Chris

Baldewin said:

Resurrecting this thread if you don't mind. In the eight months or so since you installed this conversion, how is it working? Any pros or cons to using the discovery box in the defender? I ask as I'm about to fit a 300tdi to my 90 which came from a discovery with the discovery box. I also have a V8 R380 box that I was thinking about have rebuilt with the proper input shaft to fit this conversion as well. Any thoughts would be much appreciated.

Cheers,
Chris

Click to expand...

the boxes are basically the same so no noticeable difference apart from selector mechanism,v8 boxes would need input shaft and bell housing,but still easy conversion i used to buy a lot of next to new ex mod v8 boxes and convert then to tdi ,when 300 tdi was introduced a lot of the parts in the drive train became common over the range of models ie disco rrc and defender

Thanks for the response and if I understand you correctly if one was to install a kit like Doc made you would not be able to tell the difference when driving the truck? The difference being the def vs the disco trans.

defender gear shift feels a lot more industrial....