Disco transfer box into a TD5 Defender

[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? :)

[Blknight.aus]

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

[steane]

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.

[Disco Muppet]

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

Sent from my HTC One using AULRO mobile app

[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 ?

[Ancient Mariner]

Google Ashcroft Transmissions ratio calculator
AM

[redrovertdi]

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

[loanrangie]

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.

Sent from my GT-I9300 using AULRO mobile app

[nedflanders]

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.

[DeeJay]

Not all the LT230's are the same, its been some time since I did mine, but I recall some casting & bolt hole alignments being different.
You would need to get one from the same year to avoid the differences.

[nedflanders]

Cheers

[potter]

In a word, brilliant. Low range unchanged, highway...2000rpm at 110 kmh, much quieter. I never though drive up hills in 5th even though vehicle will do it...too hard on the box and transfer case.

[pjw]

I have had no problems with my TD5 towing 3500Kg, but it improved the fuel economy and pulled better than I expected it to after one of Jose tunes. Never have it in 5th for towing as 4th does the job nicely

[flagg]

I've not done the exact thing you are looking too but I've (amongst other mods) swapped out a transfer for the ratio change: I used to have a 1:1 and went back to a 1:2. (this was on a 4DB1 however)

The biggest problem I found with the higher transfer ratio was that first gear was too tall. A pain in traffic as at idle was always faster than anyone who was moving forward at lights etc and found I had to leave really large gaps in front of me and in carparks you were always in the clutch or in low range.

just something to keep in mind - don't forget to keep an eye on 1st when you are playing with the ratio calculators.. like I did :)

[rick130]

Without running the numbers I'm guessing it's close to running 255/85's with a 1.4:1 t/case ?

If so I've found the gearing almost ideal in a tuned Tdi on the highway, but first is too tall for towing, you need second/low range for that.

[MR LR]

Don't do it.

The gearing is too high, coming from a manual td5 Discovery driver with 32's... my car is chipped, I/C'd, boosted etc, and all I want is my stock gearing back..!

[DazzaTD5]

Just some added info...

*Yes there are numerous changes in the actual transfer case housing, but keeping year for year, you generally wont have an issue.

*I normally just change out the hi/low gear set itself, this is normally due to the fact I've removed the transfer case to rebuld it.

*A TD5 (stock tune) in a Defender with stock Defender tyre size (235 85R16) running Disco 2 hi range in something like a 90, 110 with not much else on it, tow a trailer here and there, as some have said is a good mod to do and you are going to be happy with the lessor scream at higher speeds, better again if you are only running 31in tyres (31 x 10.5R15).

*If you have a 110 or 130 with lots of gear on in, for example my dads TD5 130 with everything on it weighs in at 3 ton with 265 tyres and tows the odd bobcat, Land Rover or Jeep, then you will hate it.

Regards
Daz

[nedflanders]

Thanks for some really useful info, lots to think about for and against.
Its a 90 so doesn't carry a lot of weight and the camper fully loaded weighs about 2t which gets used maybe once a month.

[Tombie]

Be advised: It will render your Cruiser Control, if fitted, useless though (wont work).

[kelvo]

Thanks for some really useful info, lots to think about for and against.
Its a 90 so doesn't carry a lot of weight and the camper fully loaded weighs about 2t which gets used maybe once a month.

2t camper? Thought your camper was only rated to 1.5t ;)

My D2 TD5 (Manual) had 235/85R16's when I bought it, standard tune. I found pulling away, especially up a hill involved a bit of clutch slipping to get moving.

Once moving everything was great, I've now put 245/75R16's on and it's much nicer to drive.

Having a tuned TD5 would probably help though.

[Tombie]

Upgrade tyres to 255-85...

Get a little more clearance, speedo becomes accurate, and slight reduction in rpm per km/h...

Plus a nice set of new rubber


Win :D

[nedflanders]

Upgrade tyres to 255-85...

Get a little more clearance, speedo becomes accurate, and slight reduction in rpm per km/h...

Plus a nice set of new rubber


Win :D

I had read that there are different coloured speed senders and all i need to do is get a different one, not sure which one though.

[MR LR]

I had read that there are different coloured speed senders and all i need to do is get a different one, not sure which one though.
That is for pre-td5 vehicles.

[nedflanders]

Would a Disco sender work?

[MR LR]

Would a Disco sender work?
Td5's and up take speed from the senders at the hubs (which work the ABS and TC).

To correct the signal you need a speedo correction unit (it's all electronic), truspeed used to make this, but I believe they are no-longer. Steve2223 has found an alternative I believe, try contacting him.

Or just change to 255/85's ;)

[Dopey]

Ashcroft sell a speedo correction unit...
It is a "speedo healer" brand, also commonly used on custom motorbikes.

Ashcroft Transmissions (http://www.ashcroft-transmissions.co.uk/speedo-correction-kit-c102.html)

Mike.

[Slunnie]

Td5's and up take speed from the senders at the hubs (which work the ABS and TC).

To correct the signal you need a speedo correction unit (it's all electronic), truspeed used to make this, but I believe they are no-longer. Steve2223 has found an alternative I believe, try contacting him.

Or just change to 255/85's ;)
Implications also being that a Disco2 transfer case wont work in a Defender because of the omitted speedo drive.

[nedflanders]

Implications also being that a Disco2 transfer case wont work in a Defender because of the omitted speedo drive.

Isn't it just blanked off, I doubt Land Rover went to the expense of different cases, but stranger things have happened :)

[bee utey]

Isn't it just blanked off, I doubt Land Rover went to the expense of different cases, but stranger things have happened :)
The speedo drive isn't in the case, it's in the output housing which should be swappable between transfer cases. I found this picture from pirate 4x4 that shows a housing with and without the drive. Whether its just plugged or not machined I have no idea.

https://www.aulro.com/afvb/images/imported/2015/05/743.jpg

[MR LR]

No reason you can't change to a mechanical speedo, you'd just need to trick the computer into thinking it still tells you how fast you're going!

[simmo]

I'm going to do the same modification, I have the disco transfer case already.

Yes I do have to change over the output casing and the handbrake etc. the defender rear housing has the speedo sender in it.

My 110 tdi (VGT, APT intercooler, and minor fuel pump tuning), seems to have the torque to pull the higher gear now, I find I'm in 5 th gear early and regularly driving at 70 kms/h in 5 th. The disco TC will make 5th for highway speeds, say above 90 km/hr only

I figure if I have to tow something heavy I'll just stay in 4th, I do tow locally with a trailer of sand and gravel etc. I can imagine with the higher disco TC , 1st gear take offs might be annoying, the 300 tdi defender is a bit gutless there already. But it's no problem for me, I already use low range and change up to high range for a difficult start with a big load.

Given the 90 is lighter etc , I'm thinking it is a good mod for touring and general commuting etc. ( ignoring the speedo problem), the issue of difficult starts with big loads can be over come using the transfer case. cheers simmo

[nedflanders]

Looks like I may just get a high gear set from a Disco transfer case as someone I know is swopping his T-Box for one with a CDL and it will give me a chance to sort out my seals on the intermediate shaft. Speedo correction isn't really a concern as I'll get a speedo healer from ashcroft, as this is calibrated by using a GPS should end up with a more accurate speedo anyway ;)
Never tried using the low range as a pull away gear for towing, do you just change from low to high like any other gearchange or is there a technique ?
:)

When we tow and for the majority of the time the 90 is empty (except for 2 kids) and with the current engine mods I'm also running out of gears, although I try not to 5th gear pulls from as little as 60kmph no problems, it's amazing how quick you can get through the gears in a tweeked TD5 :p

[simmo]

Hi Ned, yes I use low range for starting in steep hills of Heavy loads.

Plus it helps keep my high- low range selector free as well they can get a bit stiff.

If they're stiff when you go from low range to high range you tend to push hard and it beaks out of HR and goes straight through neutral into low range, you don't want that, ( big clang or crunch)

If you use your lever regularly you'll be able to go from low range to neutral to high range smoothly, just pause in neutral and lets the revs die down and ease it into HR. after a few goes it'll come easily to you.

You can go from HR -N-LR similar way. I don't do enough to be in practice but my friend can do it like a normal gear change. you can slow down in 1 st or 2nd gear HR, select TC neutral , select 2nd gear , blip the throttle and slip into TC -LR. I never bother I stop or almost stop to do the change HR-LR. My friend is a bus, truck, tractor driver, farmer, he makes it look easy. :) cheers simmo

[nedflanders]

Thanks,
It will be nice to tow in 4th at 100kph without it sounding like it's revving its nuts off, then just use 5th for downhills :)

[Tombie]

What are you towing?
5th is more then strong enough to tow 2.5t+ without issue...
Just change back down on long hills (as you should) to keep EGTs lower..

[rick130]

What are you towing?
5th is more then strong enough to tow 2.5t+ without issue...
Just change back down on long hills (as you should) to keep EGTs lower..


What Tombie said, the 5th/reverse idler is fully supported, not cantilevered as a lot of 'boxes are so is fine to tow in 5th IMO. (and I do)

[nedflanders]

What are you towing?
5th is more then strong enough to tow 2.5t+ without issue...
Just change back down on long hills (as you should) to keep EGTs lower..

It's good to know 5th is strong enough but roughly going from standard 300nm to 460nm (TD5 inside's figures) I'd rather have a more usable 4th for towing and reduce the revs in 5th when I'm not. I do always drop to 4th on the hills but then I'm dropping down to 80kph to bring the revs down, with the conversion I'll be able to maintain a 100kph towing speed in 4th.

[MR LR]

It's good to know 5th is strong enough but roughly going from standard 300nm to 460nm (TD5 inside's figures) I'd rather have a more usable 4th for towing and reduce the revs in 5th when I'm not. I do always drop to 4th on the hills but then I'm dropping down to 80kph to bring the revs down, with the conversion I'll be able to maintain a 100kph towing speed in 4th.
I originally thought this too... but then I had to use third on some hills, which was too low...

Shifting on the fly between low and high range gets old too.

[Tombie]

It's good to know 5th is strong enough but roughly going from standard 300nm to 460nm (TD5 inside's figures) I'd rather have a more usable 4th for towing and reduce the revs in 5th when I'm not. I do always drop to 4th on the hills but then I'm dropping down to 80kph to bring the revs down, with the conversion I'll be able to maintain a 100kph towing speed in 4th.

Ask Blknight how his Dad (Greynight) vehicle is going...

Its got a particularly nice tune in it :cool:

[hpal]

Be advised: It will render your Cruiser Control, if fitted, useless though (wont work).

Is this true mate? I want to put a disco transfer in my defender 2005 td5 and I have put in my home made cruise control (rocker switch and wires to ecu terminals) Is there an easy way around this? Thanks!

[Tombie]

Is this true mate? I want to put a disco transfer in my defender 2005 td5 and I have put in my home made cruise control (rocker switch and wires to ecu terminals) Is there an easy way around this? Thanks!



No. Seems the ECU checks RPM and speed and if they aren't within expectations it fails out.

You may be able to install some intercept box and modify signals but I haven't seen it successful.

Dropping the rpm using the Disco drive gear usually ends up with lower rpm with higher fuel consumption...