Lej · 2024-11-25T19:25:29+0000

Hi all,

I have a LT77 gearbox and LT230 transfer from a Discovery 1 which has become so loud that I can't bare it any longer.

I have the option to put an R380 box and LT230 in for free, what would I need to change mount wise to make it fit?

I'm also a bit skeptical as I don't know if I should go to Ashcroft and get a better ratio box for road use. At the moment it struggles going up hills and really feels like it needs a 6th gear.

I'm a novice when it comes to ratios so really not sure what I'm looking at, how would I even tell what the ratios are in both the box and transfer and even then, what are the best options for road use?

Thank you all!

Kev12 · 2024-11-25T19:33:46+0000

Lej said:
struggles going up hills and really feels like it needs a 6th gear.

You can't get both of those things at once unfortunately. To get a higher top speed (or quieter engine noise at cruising speed) would reduce the engine's performance on hills without changing down a gear. FYI the choice of transfer box affects this, the gearbox doesn't

Kev12 · 2024-11-25T19:34:52+0000

There is a plate on the transfer box with the ratio, should be a 1.2 from a D1

300bhp/ton · 2024-11-26T09:19:21+0000

Lej said:
Hi all,

I have a LT77 gearbox and LT230 transfer from a Discovery 1 which has become so loud that I can't bare it any longer.

I have the option to put an R380 box and LT230 in for free, what would I need to change mount wise to make it fit?

What engine and age vehicle?

The R380 "shorty" is a mostly direct replacement for an LT-77. (maybe a few things to solve). You can turn a regular R380 into shorty version, but you'll need to get the bits from somewhere like Ashcroft. If the gearbox is from a Disco you'll probably need to change the selector mechanism too.

The R380 is not a direct fit to some engines and uses a different seat box and transmission tunnel in a Defender. As well as different props iirc.

Anything can be swapped, but may mean more work or some bespoke hacks if you don't want to do the work.

Lej said:
At the moment it struggles going up hills and really feels like it needs a 6th gear.

I don't understand this comment.... tall gearing like a 6th would not be good for hills. So if it is struggling you wouldn't be wanting a 6th. R380 is a 5 speed anyhow.

300bhp/ton · 2024-11-26T09:25:30+0000

Kev12 said:
You can't get both of those things at once unfortunately. To get a higher top speed (or quieter engine noise at cruising speed) would reduce the engine's performance on hills without changing down a gear. FYI the choice of transfer box affects this, the gearbox doesn't

Gearbox can, as there are different ratios available. Esp on the LT-77

Phill · 2024-11-26T10:22:35+0000

300bhp/ton said:
The R380 is not a direct fit to some engines and uses a different seat box and transmission tunnel in a Defender. As well as different props iirc.

I've got the R380 Short fitted. Original seatbox and LT77 tunnel. Not sure about props as I didn't fit it.

Lej · 2024-11-26T10:28:20+0000

300bhp/ton said:
What engine and age vehicle?

The R380 "shorty" is a mostly direct replacement for an LT-77. (maybe a few things to solve). You can turn a regular R380 into shorty version, but you'll need to get the bits from somewhere like Ashcroft. If the gearbox is from a Disco you'll probably need to change the selector mechanism too.

The R380 is not a direct fit to some engines and uses a different seat box and transmission tunnel in a Defender. As well as different props iirc.

Anything can be swapped, but may mean more work or some bespoke hacks if you don't want to do the work.

I don't understand this comment.... tall gearing like a 6th would not be good for hills. So if it is struggling you wouldn't be wanting a 6th. R380 is a 5 speed anyhow.

Ah, so a bit of work required for that then. Which is fine just trying to weigh up my options.

Currently I have a short bell housing mated to a discovery 200tdi, LT77 and LT230 all these parts were on my defender before I bought it, everything suggests it's been taken from a D1.

What I meant by 6th is separate to hills, I would like it to be a bit better on hills, it handles them ok at the moment but she struggles on steeper stuff.

On straights she gets up to speed fine, but the engine has so much more to give. In essence I would like it to be better for road use than off road, if I really pin it the engine will be screaming in 5th, but isn't going particularly fast.

Thanks for the replies all, helps massively

Lej · 2024-11-26T10:30:36+0000

Phill said:
I've got the R380 Short fitted. Original seatbox and LT77 tunnel. Not sure about props as I didn't fit it.

Interesting... Would this work on a short bell housing?

300bhp/ton · 2024-11-26T11:21:26+0000

Lej said:
Ah, so a bit of work required for that then. Which is fine just trying to weigh up my options.

Currently I have a short bell housing mated to a discovery 200tdi, LT77 and LT230 all these parts were on my defender before I bought it, everything suggests it's been taken from a D1.

What I meant by 6th is separate to hills, I would like it to be a bit better on hills, it handles them ok at the moment but she struggles on steeper stuff.

On straights she gets up to speed fine, but the engine has so much more to give. In essence I would like it to be better for road use than off road, if I really pin it the engine will be screaming in 5th, but isn't going particularly fast.

Thanks for the replies all, helps massively

If I recall you were also asking about 285 sized tyres. These are quite big and if you are running the Disco gearing, you will be over geared to some extent. Especially with a Tdi engine.

A Disco LT-77 will have the tall gear set and the 1.2:1 transfer box. Disco would have come on small wheels though. A 200Tdi factory Defender would have had the same gearbox ratios, but the 1.4:1 transfer box, but also taller tyres. Thus both vehicles having very similar overall gearing and mph/1000rpm in top.

Assuming you do have have the gearing setup you say, that should be sufficient to be able to cruise at 75-80mph.

A Tdi engine will really lack power to run quicker. Is your engine tuned or modified?

A modified Tdi runs a lot better, but will also run hotter, so you may have to back off at high speed or long climbs to lower EGT's.

Tall gearing may also mean you won't be able to pull 5th in some scenarios, forcing you to drop to 4th and maybe have a lower top speed than shorter gearing that would have allowed you to maintain 5th.

Your setup is already quite tall:

If your current setup struggles on hills, I'd say going to smaller tyres or a 1.4 transfer box would improve things.

If you want to spend the cash, you can get an aftermarket overdrive like a RoamerDrive to give an extra low cruising gear, but they ain't cheap.

Ultimately for high speed road use, the Defender is the wrong vehicle. You'd be much better off buying something more suited to that if that is your ultimate goal.

Lej · 2024-11-26T11:36:31+0000

300bhp/ton said:
If I recall you were also asking about 285 sized tyres. These are quite big and if you are running the Disco gearing, you will be over geared to some extent. Especially with a Tdi engine.

A Disco LT-77 will have the tall gear set and the 1.2:1 transfer box. Disco would have come on small wheels though. A 200Tdi factory Defender would have had the same gearbox ratios, but the 1.4:1 transfer box, but also taller tyres. Thus both vehicles having very similar overall gearing and mph/1000rpm in top.

Assuming you do have have the gearing setup you say, that should be sufficient to be able to cruise at 75-80mph.

A Tdi engine will really lack power to run quicker. Is your engine tuned or modified?

A modified Tdi runs a lot better, but will also run hotter, so you may have to back off at high speed or long climbs to lower EGT's.

Tall gearing may also mean you won't be able to pull 5th in some scenarios, forcing you to drop to 4th and maybe have a lower top speed than shorter gearing that would have allowed you to maintain 5th.

Your setup is already quite tall:
View attachment 330747

If your current setup struggles on hills, I'd say going to smaller tyres or a 1.4 transfer box would improve things.

If you want to spend the cash, you can get an aftermarket overdrive like a RoamerDrive to give an extra low cruising gear, but they ain't cheap.

Ultimately for high speed road use, the Defender is the wrong vehicle. You'd be much better off buying something more suited to that if that is your ultimate goal.

Woah, lots of info! Love it!

Correct, good memory! You've already figured the broader picture here, I didn't want to overload info in my original post, but you've twigged.

So I am looking at downgrading my tyres to a smaller size A/T, currently I have Mud terrains. Along with that I have advanced the pump, boost pin, full face intercooler and other bits and bobs, which has helped massively to speed it up, especially pulling away from junctions. I do have an EGT sensor and upgraded cooling (electric fans etc) and it does run at a nice temperature, it hasn't really spiked to be honest.

I am happy with the way it runs and drives, the speed is fine too. It's more the fact that the engine will be sat at high RPM when cruising on the motorway. It does like you say sit at 80 no problem, and would probably go much more than that if I had the balls...

What is the website you are using for those readings?

Thank you for the help, I appreciate it!

300bhp/ton · 2024-11-26T11:45:18+0000

Lej said:
Woah, lots of info! Love it!

Correct, good memory! You've already figured the broader picture here, I didn't want to overload info in my original post, but you've twigged.

So I am looking at downgrading my tyres to a smaller size A/T, currently I have Mud terrains. Along with that I have advanced the pump, boost pin, full face intercooler and other bits and bobs, which has helped massively to speed it up, especially pulling away from junctions. I do have an EGT sensor and upgraded cooling (electric fans etc) and it does run at a nice temperature, it hasn't really spiked to be honest.

I am happy with the way it runs and drives, the speed is fine too. It's more the fact that the engine will be sat at high RPM when cruising on the motorway. It does like you say sit at 80 no problem, and would probably go much more than that if I had the balls...

What is the website you are using for those readings?

Thank you for the help, I appreciate it!

Ratio Calculator

This software is designed for you to accurately compare and calculate the gear ratios of your landrover when the gearing is changed from stock by different tyres etc. We are interested in the combination of 5 factors which make up the gearing. 1) Gearbox 2) Transfer case 3) Overdrive or...

ashcroft-transmissions.co.uk

Phill · 2024-11-26T13:58:59+0000

Lej said:
Interesting... Would this work on a short bell housing?

Mine is a short bellhousing. Isuzu engine to a R380 Short to a 1.2 Transfer box, which is terrible in Wales.
Changing it to a 1.4 on Saturday, thank christ. If the last owner was trying to make it undriveable on anything but a flat surface, he succeeded admirably.

Lej · 2024-11-26T14:14:04+0000

Phill said:
Mine is a short bellhousing. Isuzu engine to a R380 Short to a 1.2 Transfer box, which is terrible in Wales.
Changing it to a 1.4 on Saturday, thank christ. If the last owner was trying to make it undriveable on anything but a flat surface, he succeeded admirably.

Hah! Yes, it is quite hilly in that neck of the woods!

Would there be much of a change on flat roads changing to the 1.4?

Thanks Phill!

Phill · 2024-11-26T14:43:10+0000

I'll let you know, but it's supposed to be better for general driving on all terrains, and towing.
To be fair, the 1.4 is the standard box on a 90/Defender (ignoring the 1.6 on some). Suffice to say I now know why Land Rover didn't fit the 1.2 to Defenders. It's weak (not structurally, just weak at dragging it's arse anywhere other than a flat road)

Kev12 · 2024-11-26T15:05:24+0000

As mentioned above somewhere, defenders have taller tyres than a discovery too

tottot · 2024-11-26T15:17:26+0000

Having driven 200tdi Defender and 200tdi Discovery, when it comes to cruising down the main road [no motorway's in my home county] the Disco is the winner but if hauling heavy trailer up hill down dale Defender every time.
Not to say Disco can not do it but it will be in lower gears doing so.
Defender at 75-80! Good way of burning up a lot of fuel. Probably the worst drag coefficient car in the world.
Both on standard size tires.

Lej · 2024-11-26T15:33:42+0000

tottot said:
Having driven 200tdi Defender and 200tdi Discovery, when it comes to cruising down the main road [no motorway's in my home county] the Disco is the winner but if hauling heavy trailer up hill down dale Defender every time.
Not to say Disco can not do it but it will be in lower gears doing so.
Defender at 75-80! Good way of burning up a lot of fuel. Probably the worst drag coefficient car in the world.
Both on standard size tires.

Hah you're not wrong there! Not to mention it's terrifying

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