lt77/r380 in a series

[jericho]

Help please.I want to fit a 5 speed box and lt230 transfer to my 2a.The 300 tdi is already in and running well through the series transmission,but i want to change the box. 5 speed onto series transfer box sounds too hard for me - no machining skills.So come on,someone must have the knowledge!I want to know about mountings,propshaft lenghths,crossmember problems,etc.

Lt 230 will either be converted to part time 4wd,or i will fit cv joint axles.not decided yet.

Currently,series box is in standard position,tdi is of course in front of it - I do not want to move engine forwards to overcome prop shaft issues.

Any comments?

[Tonk]

crossmembers will have to be moved and gearbox mounts refabbed, propshafts altered, floors,tunnel and seat box modded.

fridge freezer might be able to give you a few more exact pointers cos he's doing this at the moment

[jericho]

Come on,Fridgefeezer !!!

Is there a diference in size/length between lt77 and r380 ?

[Tonk]

same length, they are the same castings basically and both use the lt230, the only difference is the length of the bell housing on the front, 4 cyl, v8 etc, 4 cyl is the shortest.

doing this mod will add about 8" to your transmission length, so your rear prop will become pretty short, especially if you have a swb, so prop bind could be an issue.

[FridgeFreezer]

What Tonk said really - you need to get the tape measure out and work out prop lengths, if it's an SWB you may want to shuffle the engine forward a tad - saying that though the 4cyl bellhousings are far shorter than the V8.

Unbolt the gearbox/transfer box mounts from an old coiler chassis or order them new:

NRC7136 - LH Chassis barcket

90575585 - RH

NRC5890 - Mounting rubbers x2

SH112252L - Long Bolt x6

NH606041L - Nut x6

WA108051L - Washer x12

You need to weld some tube in to reinforce the chassis where the bolts go through.

You need to make sure your manual box is from a Defender (has the gear shift brought forward on an extension casting from the top of the gearbox) as RR/Disco ones don't have this and can't be converted without a complete stripdown of the gearbox

This is a defender type:

These are RR/Disco:

Stuff about LT230 2WD conversion is here: Clicky

Edit: LT77 and R380 are not quite the same length, R380's were an inch or so longer so some R380 input shafts & bellhousings are an inch or so shorter (V8) I'm not sure if this is the case with the 4-pots but I'd check before assuming. Also some of the bellhousings are hard to get hold of - took me ages to get a V8 one and it took Al even longer to get a stubby one (why does that sound rude?)

[MECCANO]

for any one else thinking about doing it this gives you an idea of the length

this gives you an idea of how theoretically its going to fit

BLUE = standard series gear box ( the circle represents the gear knob, and the lines to the right are the faces of the front and rear output flanges on the transfer) if you couldnt work it out

RED= Lt77 ( same rules apply apart from the two knobs)

GREEN= 200tdi with the nose of the water pump show, with the viscous fan removed

A bit of a colour change + some bling

Oh the lt77 rear flange ( line ) is about 1.5 inches further back than the standard series

[Tonk]

Oh the lt77 rear flange ( line ) is about 1.5 inches further back than the standard series

is this using the series transfer box on the back of the lt77 or the lt230?

i've got a series t/box on the back and it works out that the rear output flange is 108mm further back than standard, this is all dependant on what thickness you manufacture the adaptor plate from of course but i made it from 20mm thick aluminium, i dont think you could make it any thinner.

[Jon White]

Mate of mines just put an LT77 and 230 into a series 2 and he had to move the crossmember thats behind the gearbox back about 2" otherwise he found he couldnt get the handbrake drum off!

You also find the transfer box lever will foul the seatbox so has to be abandoned and you'll have to make something else up to operate the high/low and diff lock.

I thought the R380 was a tad longer than the Lt77 but I may be wrong...

Jon

[Tonk]

i thought lt77 and r380 was same outside casting(?) dont know about ali output casing though

[MECCANO]

sorry should have seaid. this is with a lt77 and lt230

unlike what jericho is doing im planning the oposite. try and keep the prop shaft lengths the same and move the engine forwards. you can see the difference between the blue and red bell housing lines.

which means im goign to have flip all room for the rad/intercooler and fan arrangement

[Tonk]

are you planning to leave the rad in standard place? if so you have got much room to move everything forward, unless you stick a 90 front end on and move the rad

[MECCANO]

no im shifting everything above the frist memeber. it will give me a 6inch gap to fit everything. im hoping to do it with more modern thinner alu rads intercoolers etc.

[jericho]

Done a quick measure.If you leave the engine in place,and swap series gearbox/transfer box for defender lt77/lt230,the rear prop will be about 4 inches shorter and the front prop about 7 inches longer.

Spoke to someone on the weekend who as done a couple of these conversions - he did manage to squeeze the high/low knob in front of the seat box - didn't ask details.He recommended to cut out gearbox cross member and replace with military type removable one.Also it is necessary to cut a scallop out of the bulkhead cross member to allow room for longer front prop on full droop.

I have now bought an lt77 to fit,and in the process of searching for one discovered that early 90/110 lt77s have sightly different ratios to all the later ones (higher first and lower fifth),dispite the fact that several landrover parts dealers told me they were all the same.I confirmed this fact with Dave-ashtrans-ashcroft on this forum- so three chears for LR4X4.com.

For the near future I will maintain series uj front axles.Is there any good reason why I can't unlock my freewheel hubs,lock the centre diff on lt77,and have 2 wheel drive?

[bill van snorkle]

For the near future I will maintain series uj front axles.Is there any good reason why I can't unlock my freewheel hubs,lock the centre diff on lt77,and have 2 wheel drive?

You should only notice the lack of constant velocity joints in the front axle on tight turns if at all. After all many fulltime 4wd US built vehicles in the 1980's had UJ's in their front axles. Hopping of the front end under accelleration with a bit of steering lock wound on is more a product of poor axle location provided by the short series front springs and shackle location rather than the type of driveshaft joints employed.

To answer your question though. There is no reason why you can't do as you propose. there may be an increase in driveline backlash when compared to the normal constant 4 wd arrangement, but that would depend on the condition of your front propshaft and all the components in your front axle/diff assembly.

Bill.

[Gremlin]

For the near future I will maintain series uj front axles.Is there any good reason why I can't unlock my freewheel hubs,lock the centre diff on lt77,and have 2 wheel drive?

You will hate it! belive me i tried it and the amount of backlash is annoying, you get a terrifying bang when you let go of the clutch.

I went to a stage 1 v8 front axle which sorted all the mishaps of a UJ front, or just convert the lt230 to 2wd!

Grem

[bill van snorkle]

You will hate it! belive me i tried it and the amount of backlash is annoying, you get a terrifying bang when you let go of the clutch.

I went to a stage 1 v8 front axle which sorted all the mishaps of a UJ front, or just convert the lt230 to 2wd!

Grem

I think you may have had a knackered centre diff. With constant 4wd all the working clearances in both propshafts and front/rear differential/axle assemblies must be taken up when you let the clutch pedal up, so it's a bit of a toss up which drive mode would give the most backlash.

An old series front end will have a bit of play in both freewheel hubs/halfshaft couplings, there will be play in the halfshaft/ side gear couplings, there will be backlash in the differential bevel gears themselves, crown wheel to pinion backlash, propshaft slip joint wear. All these clearances(backlash) added together can be considerable and in conjunction with constant 4wd could well exceed the backlash of the loose fitting centre difflock dog clutch driving just the rear diff.

Bill.

[V8Nick]

Hi,

I'm a bit behind jericho with my project. I have my 1970 S2A 88" 2¼ petrol on the road at the moment with an Ashcroft Hi-ratio transfer box, but I also have a 3.9 V8 and a conversion kit to suit the series gearbox waiting to go in (got no flywheel though). I also have an SD1 bellhousing at the back of the shed somewhere.

However, I'm interested in finding out if I could go to an R380 with the series t/box.

Oh and MECCANO, what 3D package are those models from? It looks like 'Inventor'. You wouldn't concider letting me have a copy of that model would you? Please?

Cheers, Nick

[jericho]

R380 and series transfer box.

It is no doubt possible,but has to be a lot of work to make an adapter to mate the two.Shout out for Tonk,he must be the expert.

Surely easier to use R380 and lt230 and convert to 2wd or whatever.

[Jon White]

Tonk and I both run Lt77 mated to series transfer box. We both agree its too much work to be worthwhile and wouldnt bother with it again. Involves making up adaptor plates, bearing carriers and custom making an input gear, along with a right old mish mash of landrover and sherpa bits.

If you've plenty of tiem on your hands and access to a full equipped machine shop then go for it, otherwise dont bother!

Jon

[Tonk]

Agree with Jon, its alot of work, if i done lt77 conversion again then i'd stick the lt230 on the back of it, just so much simpler, was a good engineering challenge though.

[Andy]

i think R380 & LT77 are the same length, at least the difference is very small. otherwise i couldnt have replaced the LT77 in my disco with a R380 & used all the same props/mounts etc gearsticks are in the same place as before as well.

[FridgeFreezer]

As I said before, R380's are almost identical but about 1" longer, this is usually taken up in a different bellhousing which makes the overall package the same length as an LT77 + bellhousing.

R380's are longer, see?

[Andy]

ahhhh i always think of the bellhousing as part of the gearbox, hence my confusion.

all is clear for now, im sure i'll be back later to sound dumb on another subject though.

[bearpig]

On 10/12/2006 at 2:38 PM, Gremlin said:

You will hate it! belive me i tried it and the amount of backlash is annoying, you get a terrifying bang when you let go of the clutch.

I went to a stage 1 v8 front axle which sorted all the mishaps of a UJ front, or just convert the lt230 to 2wd!

Grem

Sorry for digging an old thread, but I've got a sIII with a 2.5 NA diesel (12J) and a LT77 box in it, and ever since I bought it I've been trying to diagnose this issue.

When the free-wheeling hubs on the fronts are set to 4x2 and the front diff is locked, theres large amount of backlash and a decent thunk when taking up drive.

Did you ever get to the bottom of it (was it a buggered center diff)?

[FridgeFreezer]

@bearpig is your setup LT77 + LT230 then? What vehicle is it in?

You say the front diff is locked... I assume you mean the centre diff (in the LT230) not that you've got a locking diff in the front axle?