Discovery Box in a TD5 Defender, my experience

Good morning everyone.

I thought I would share my experiences since fitting a discovery transfer box to my TD5 110.
I had been deliberating over this for over a year, and eventually decided to source a box and get it stuck on at the same time as the a clutch and DMF renewal.
I found some good information online but nothing that gave a good daily experience of it.
I tend to do quite a lot of motorway miles, travelling from Cornwall to London to Norfolk. I find the Landrover a comfortable and enjoyable cruiser, I don't mind doing the miles in her at all. She would seem to naturally cruise at 60, pushing it up to 70 was hard work and would always end up back at 60 (potentially a DMF issue too)

Gears
So I have fitted a Disco box, since then the Landrover is a completely different vehicle.
- 1st is now a useful gear, it doesn't feel too long and allows you to pull away without cars almost hitting you from behind. I have a steep junction coming out of the farm and it manages with that.

I find myself getting up to traffic speeds when joining roads or pulling away from lights much quicker in fewer gears, making the whole experience much easier. Where 1st, 2nd and 3rd used to be gears rarely used once you are going, they are now required, 30 in 3rd is now the norm rather than 4th.
I use 4th a lot more now when I'm driving on B roads, and it seems right. I believe that 5th should be a cruising gear, to be used at 50 and above. Historically most of my B road driving was done in 5th. Come to mention it, my Landy practically lived in 5th, the other gears were just there in order to get me to 5th. That has now changed, for the better.

Hills
I live in Wilshire, we certainly have no shortage of hills here. Where the Landrover used to pull up hills in 5th you may need to shift to 4th. But to be honest that doesn't really bother me as 5th should be a cruising gear not a do everything gear.
With the 'longer' feeling ratios pulling up hills seems easier as 3rd-4th is actually a decent speed and wont leave queues of traffic behind you.

Towing
I tow the occasional flatbed with straw or other gubbins on it, but i cant see this being an issue. May be slower up to speed and may need to change later and rev higher, but not a game changer for me. However if you are often dragging 3 - 3.5 t around you may want to consider a small tune just to make up for it.

Ratios
I am fortunate enough to have a factory counter on the Landy.
Historically 60 was achieved in 5th at around 2500, now its 2150-2200. It is noticeably quieter and more comfortable.
50 in 5th is basically 1600 so great on the A303 which has long stretches of 50, she just bumbles along, dead silent and not labouring.


I haven't done a long journey yet (due to tomorrow) so I can't comment on long motorway driving yet. I will do when i'm back.

I should also mention that this is a bone stock Td5 (110), not even an EGR blank kit (manifold hex has rounded). She has done 125,000 miles and is on your standard Landrover alloy (image below)

wheels and BFG All Terrains

I will try and keep this up to date with my experiences over the next few weeks. This modification strikes me as being very accessible, the transfer box was £120 and I was charged £40 to fit it (the gearbox and tranny was out to replace clutch and DMF) but even another £150 to fit would make it a value for money modification, it really does change the vehicle for the better.

On another note, if your TD5 is a bit of a circus around 3000rpm and above, have your DMF changed. Mine was really hard work to rev before, and now since a new Valeo DMF was fitted its a lovely free revving engine, which pairs very well to the 1:22 Disco box.

Very interesting, thanks. Our 110 (with 200Tdi) is very 'busy' at 60mph. It's the noise more than anything, you can't hear yourself think
The problem is, in our case, it's regularly towing a lot of weight- maybe 2.5 tons and I'm worried it would struggle out of junctions with the trailer on the back, especially with the 7.50 tyres if I fitted a 1.2 transfer box.
The Discos are fine of course, but the tyres are smaller.. Decisions decisions

Good to know. Also been contemplating this for years... On my 90 the gearbox was replaced so I had a higher ratio 5th gear fitted which made a world of difference! Though the 110 is standard so this is worth thinking about again

I think towing (alot) with a stock 300 may be an ask, unless you changed your tyre size or tweaked the engine.
I also think a bit of a paradigm shift in the way you (I) drive would need to take place. These days it seems people (someone I work with) expect to be able to leave a vehicle in 1 gear and achieve a speed range of 30-70mph in that given gear (often 5th). Some engines can do this, and some can't. In any respect that cant be the most effective use of a gearbox, imagine what the engine could pull with a longer final gear (now being seen with the addition of a 6th to most new vehicles). I guess what I'm trying to say is; this modification could work with any vehicle if you used more of the engines rev range and utilised more of the gears in the box.

BankZ
Definitely worth a consider, I will put some more pictures and maybe videos up to give folks a better idea.

Thats worth doing! Also you know you can tag members in posts by using the @ symbol? @MungoPark

@bankz5152 good to know! Ta

On a TD5 with 33s or smaller, Jr's a no brainer in my opinion especially if it's tuned a little bit.

My last 110 with the disco box, remap, VNT, Intercooler etc was lovely at motorway speeds to the point even once when the gearbox **** itself, it was still usable for the rest of the journey with just 4th gear as it's a direct drive. 1st, 2nd, 3rd, 5th and reverse were gone lol.
That was with a trailer with and car on the back on the way to a trackday too!


Huge saving in fuel too as it gives almost 50 miles etc to a tank if doing alot of higher speed driving like motorway etc

I'm debating if I'll do it on my current 110 as I have the transfer box, just to decide if it's abit too much as now have 35s although, have more power too with a freshly rebuilt engine and proper remap to suit the mods.

Might go with an overdrive maybe as 1st could be abit too tall when pulling away when towing as I do quite abit of trailer work.

@DaveM-sport
Cant comment on larger tyres, but as bone stock Td5 loves it. Might consider a light remap next but don't feel like it needs it.

I went of overdrives for the price and the difficulty in finding them (and their spares).

But you are right, when towing heavy loads 1st is the weakest point.

David_Cooper said:

Very interesting, thanks. Our 110 (with 200Tdi) is very 'busy' at 60mph. It's the noise more than anything, you can't hear yourself think
The problem is, in our case, it's regularly towing a lot of weight- maybe 2.5 tons and I'm worried it would struggle out of junctions with the trailer on the back, especially with the 7.50 tyres if I fitted a 1.2 transfer box.
The Discos are fine of course, but the tyres are smaller.. Decisions decisions

Click to expand...

200Tdi is eminently tunable... some info here:-

http://www.jeremyjfearn.co.uk/intercooler.htm

my 300 ( in a D1 auto ) has one of his setups on, and its very good IMHO... and 145HP should pull the higher ratio quite nicely, I would have thought.

( I'm not sure how much Jeremy Fearn does nowadays - but the site is still live, and is full of useful info )

Out of interest, what did you guys do with your 1.4 boxes?

I was planning on doing the opposite and looking for a nice tidy transfer box!

Anyone near Bristol?

I have done the same with my 200Tdi 90, due to the fact the T box was getting quite noisy and I'd just had a replacement (2nd hand) gearbox put in my disco and as it came with T box I had a spare.
I have a long straight hill coming up to the house which I use as a test tool.
Some years ago I had to replace the centre exhaust section so went for a straight through stainless jobby, took it for a run and the 90 got to 50 mph at a point which was only ever 46-47mph before, result.
Changed the T box for the spare disco one and as you say transformed the cruising speed experience, much more pleasant to drive at 60mph but 3 to 4 was now at 30mph and 4 to 5th was now at 40mph. The drag up the hill was down to the old 46/47 mph as before so not a lot lost really.
At this point I fitted some new discoverer 235/85 stt pro rubber and I am sure they are a fair bit taller than my old worn out G90's, now this really was slow going, 45 mph at the given point on the hill if I was really really trying. Something had to be done.
After a fair bit of worrying around I decided to bite the bullet and have a go at tuning the FIP, trying it out on my disco 1st as that is the unloved one of the two. Wow, I am now easily getting to the 50mph mark again, no smoke (I did'nt go too far with the tuning) but the engine is now quieter than before even allowing for the reduced revs, and I have to say cruising at 60mph is just nice.
Havn't had chance to check the fuel consumption yet but I would be suprised if it was not better than before. By the way all speeds are checked with a gps.
Happy bunny, should have done all this years ago.

@rathomas
Funnily enough I am looking to sell mine and I'm driving up to Bristol (ish) this evening. If we are quick enough we might be able to make a plan.

Back to my experiences after putting 350 odd miles through the new box. The drivability of the Landy is noticeably better (even my mrs jumped in it and mentioned how much better it was) I seem to be cruising at 70 more now and keeping up with traffic much better. One thing have noticed is a drop in fuel economy, potentially because I'm driving that bit faster. I will keep an eye on this, as I have only put one tank of fuel through it.
Heading to Cornwall this weekend so will keep everyone posted.

All in all, so far, very impressed.

just to add a little the LT 75 was fitted in rover sd one minus the transfer case apparently these gearboxes are fitted with a high ratio 5 th gear . i wonder if the transfer case will fit the car version of this box or is the output shaft different .... any thoughts

@Dean Whittam can't comment on that, although I'm sure someone will know. Sounds like an interesting mod if it's possible

MungoPark, you have summed up my experiences of the Disco transfer box perfectly. Actually, mine is a Disco 2 box, so ever so slightly taller geared again.

A couple of points to add...
My 110 had the Disco box in it when I bought it, so I've not owned a Defender with the standard box in it
Mine is a 200Tdi on 265/75/16s, and is more than happy for the driving I do
Totally agree about 3rd being the 30mph limit gear...you are sometimes looking for "3rd and a half" as 4th is labouring the engine a bit
I've towed about 2.5t in a big twin axle Ifor around rolling Warwickshire with no problems at all...however going on holiday with a big trailer tent, bikes, dinghy & outboard and the multitude of clobber required for a week's camping with a 7 month old, I did feel it a bit on really steep Welsh mountain passes.
Many people...non Land Rover owning passengers...have said they are surprised how "fast" my Defender is. And that's without me mentioning anything at all about the engine/box combo
It is 100% totally capable of keeping up with modern traffic speeds in pretty much all situations. I can even overtake stuff on B roads etc if needed. It really does give useful, practical speed and performance. And I'm not just being kind to the Land Rover here or getting used to slower vehicles...without sounding like too much of a tw@t my other car is a Porsche...(which will break the national speed limit in 2nd gear...)
Low range is the same so off road ability is not compromised.
I hope that I will have my 110 until my dying day but should it ever be replaced the absolute first job I would ever do is fit a Disco box...unless I suddenly took up hill farming there's no way I'd even entertain a standard box in a Defender now.

With regards to fuel consumption if you have habitually been driving at say 60mph, then fit the disco T box and for the same engine revs drive at 70mph (don't really know if the revs would be the same but it feels like it) then even though the revs are the same the air resistance or can we call it drag will be increased by the square of the increase in speed. I think thats right though its 45 years since I was involved in aircraft.
Yes the revs might be the same for the increase in speed but you will probably be putting more right foot down so using more gas.
I suspect @wammers will have an opinion on that, more knowledge than me anyway.

@frog hopper I think you are dead right there, the increased wind resistance will require greater effort to move forward. I have found significant fuel savings on B road and 60mph motorway speeds. But push up to 70 and she starts to drink.

For reference 70 with the disco box is exactly 2500 rpm, which is what 60 was on a conventional defender box.

Ah thanks Mungo, I always wondered what sort of revs my engine was doing but after a few searches turned up nowt I gave up.

Right, sorry for the delay all been a busy couple of weeks. I have put 2500miles through the box, mostly on motorway driving. Verdict is that its a vast improvement when travelling long distances and general tar driving. I used it as a gun bus over the weekend, with 6 people and deep claggy mud i needed to shift to the low box (I may have needed to with a normal T-box anyway) however in that situation you do feel that 1st is a touch long. Maybe a touch more power out of the engine would overcome this.

I would still recommend this mod. Drove from Norwich to Bodmin moor over Christmas, sat at 70 the whole way, got 480 miles out of a tank and didn't break a sweat, absolute dream.

Happy with the box so I have a good defender T-box up for grabs, near Salisbury.

Anyway as promised a speed/rev counter photo.

Without wishing to sound like too much of a nazi let's jut hope that was the passenger taking photos whilst driving...

Anyway, main point of the post was that you should not have noticed any change in low box as they are the same ratios regardless of box, to the best of my knowledge it's only high box that's different.