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#Post#: 51464--------------------------------------------------
5 speed gearbox conversions (LT77/R380)
By: estwdjhn Date: February 10, 2013, 3:37 pm
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Since apparently I did this once, and now have half a clue about
this (and thus end up writing the same stuff on new a thread
about once a week), here be an attempt at an idiots guide to the
why's and wherefores of fitting 5 speed gearboxes into series
landrovers.
Before we begin, a quick q&a session.
Q) Does a 5 speed fit without cutting anything?
A) Sort of. I cut a chunk out of my seatbox, but could have used
a 110 seatbox complete instead. Depending on suspension
settings, and what you do with the front propshaft, you may need
to cut a scallop out of the bellhousing crossmember for the
front prop to clear. I didn't, but I have an ex-mod chassis with
a scallop already in there. I also altered my bulkhead a little
round the transmission tunnel, to make that bit the same as a
late series 3 (I actually did this ages ago, as it makes getting
at the engine/gearbox bolts much easier).
Q) Does it work well?
A) I think so. Mine hasn't blown up yet (unlike the previous
thirteen 4 speeds) and my truck cruses very nicely at anything
between 50-80mph. Lo ratio also ends up back where it should be,
rather than being a bit too high as it is with just 3.54:1
diffs.
Q) Does it have the right number of rivets? If not, why not?
A) I don't care, it's my landrover, and it was a £100 breaker
when I bought it 10 years ago anyway. Go and play counting
rivets on a forum where people care about things like that, when
they're not dreaming of elton and barrymore >vom<
Q) What does it cost?
A) It all depends what you pay for your gearbox. I reckon my
conversion totted up to about £100, but my gearbox was partially
broken and very cheap. That said, since I bought my gearbox a
bit over a year ago, there seems to be more about, and at lower
prices - probably as more early defenders rust away the
situation will get better. Add about £50 over what you pay for
the gearbox, and you won't be far out.
Q) Is it permanent 4wd? Does this matter?
A) It can be, or it can be selectable 2wd like a series - it all
depends what you do with your transfer box. Does it matter?
Pages have been written about this on the Internet, from which
you can conclude that a lot of teenagers who probably haven't
driven a car yet like arguing. I went for selectable 2wd,
because its g8 4 drifin iniit m8. :finger:
Q) How long does it take to fit?
A) I spent about an evening modifying my transferbox, and a
(long) day fitting the gearbox. I did cheat and fit the gearbox
from underneath, working in a pit with a gearbox jack. If you
haven't got that sort of stuff at your disposal (to say nothing
of my willingness to go rather "redneck engineering" to get
stuff done), then you should allow at least a decent weekend.
#Post#: 51468--------------------------------------------------
Re: 5 speed gearbox conversions (LT77/R380)
By: estwdjhn Date: February 10, 2013, 4:33 pm
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Part 1 - bits you will need.
A series landrover
A gearbox
A transfer box
Some gearbox mounts
90-110 floor panels and gearbox tunnel
Propshafts
Clutch
Speedometer
A series landrover.
Most people here probably know what one of these is, some people
know how many rivets one has. This guide assumes you are working
with a 4 cylinder vehicle (cos 6 cylinder engines are waaaayyyy
to cool to replace with tdi's, and you probably only need a 5
speed gearbox if you have a tdi), and mostly deals with a 109"
(cos that's what I have). It is possible to fit a 5 speed in an
88" - I've seen it done several times, the main difference is
the rear propshaft ends up shorter. I'm also assuming that the
engine is in it's original position on the chassis mounts.
A gearbox
Unfortunately, not all 5 speed gearboxes are equal. There are
three main breeds of gearbox internals we are interested in, and
two main breeds of externals.
Internally you have:
LT77
LT77S
R380
These all look much of a muchness, and work mostly the same way,
but have slightly different guts. The original LL77 comes in
about 5 slightly different ratios, and is the weakest option.
It's natural home is in a 90 or 110. It is also to be found in
2wd form in various vehicles, but I would leave 2wd boxes well
alone, as they will be more work to make fit than it is worth.
The LT77S is fitted to 200 tdi Defenders, Discoverys and
Rangerovers. It has bigger bearings and is supposedly stronger
than a LT77. The easiest way to identify one (compared to an
LT77) is to look at the bottom of the bellhousing - if there are
holes in the right places for the 4 bolts that go into the sump
stiffener on a tdi, then it should be a LT77S (assuming no-one
has played silly beggars with the bellhousings)
The R380 is fitted to 300 tdi Defenders, Discogays and
Rangerovers. It is essentially an uprated LT77S, supposedly good
for 380 Nm of torque. It's easy to tell an R380 apart from an
LT77 - reverse on an LT77 is to the left of 1st and forwards -
on a R380 it's behind 5th.
Then the cases - there are "Longstick" and
"Shortstick"gearboxes.
Longstick gearboxes have short bellhousings, long gearlevers,
and the hi-lo-difflock lever behind the main gearlever. They are
found in 90/110 and 200tdi defenders. This is what we need.
Shortstick gearboxes have long bellhousings, short gearlevers
and the hi-lo-difflock lever in front of the main gearlever.
They are found in
Discogays and rangerovers. These don't fit in a series, unless
you like changing gear with the lever somewhere in the middle of
the centre seat.
300 tdi defenders have an R380 gearbox which is basically a
longstick type, but with a long bellhousing too - these are no
use either. A very few "stubby" R380s are about, with a short
bellhousing, but either you pay Ashcrofts a grand, or you have
to find a hen with teeth if you want one of those.
Unfortunately, while the internals of a "shortstick" box may be
the same as those on a "longstick". it doesn't follow that
converting one to the other is easy - unfortunately it's a nasty
messy job best done by some other mug.
A transfer box
All these 5 speed gearboxes are designed to work with an LT230
transfer box. These come in a dazzling array of different high
ratios, although the lo-ratios are all the same at 3.32:1
Here is a rough guide to ratios and where they can be found.
1.667:1 - 90-110
1.410:1 - defender 200 tdi, early MPi disco
1.222:1 - rangie/disco 200tdi , earlier 300tdi, some v8
1.211:1 - later 300 tdi Disco/Rangie
1.192:1 - V8 90/110/defender
1.003:1 - Early 3 speed V8 auto Rangie
LT230's can be found in various other places, indeed I think may
well still be in production, but these are most of the common
ones you will come across.
Sane ratios to consider for a series are probably 1.410 for
regularly heavily laden vehicles and towing, 1.222 or 1.211 for
lighter vehicles. I run a 1.22:1 and big tyres on Bitsa and am
happy, but it is slightly overgeared in all honesty. It does
make motorways very relaxing, when 70mph is just under 2000rpm.
HTML http://www.solemnwarning.net/transmission/
is a very useful
calculator for working out what happens with which pile of bits.
An LT230 is intended as a permanent 4wd unit, however it is
pretty easy to modify it by removing the guts of the centre diff
so that it drives just the rear wheels, and the old difflock
control brings in drive to the front wheels. More on this later.
As an alternative to an LT230, some people pay Ashcrofts large
sums of money for an adapter to mate a series transferbox to a
LT77. I personally regard this as a waste of a perfectly good
wad of £20 notes, not least because the final drive ratios you
then get are very fixed, and not particularly good, so I'm not
going to say more about it (not least because that's about all I
know). A couple of people on here have fitted them, I'm sure
they can fill you in if you really really MUST spend more money
than you need to.
Some gearbox mounts
I used new 110 type rubber mounts on the existing series chassis
mounts, then made bits of metal to bolt on the gearbox to suit
(More on those bits of metal later). 110 rubber mounts are very
much like series mounts, but a bit fatter, and seem to absorb
vibration better. They are only a couple of £ each. I would
suggest fitting them all round (i.e. on the engine mounts too)
if you have a tdi, although you have to trim little off the
engine ones to get them to fit.
90-110 floor panels and gearbox tunnel
As it says on the tin. They pretty much bolt straight in, I had
to bend one bit of one panel to get it on the bulkhead. You need
a drivers floor plate, and the two bits that form the tunnel as
a minimum - it's possible to trim a series passenger floor to
fit. You also ideally want the sound deading plastic cover that
sits over the tunnel, and the bit of foam that lives on top of
the gearboxes.
Propshafts
My truck uses a 200tdi disco rear prop on the back (it was just
long enough), and a shortened 200tdi disco rear prop on the
front. Shortening a disco propshaft is pretty easy to do, mine
was homemade, and I will cover that later in this guide.
A clutch.
You need the original type of clutch found on a 200tdi. Buy
decent stuff if you don't want to change it a week later. Fit a
new clutch-fork at the same time, they are prone to fatigue and
failure means splitting the engine and box to fix. I used the
original master cylinder to drive the clutch hydraulics via a
disco slave cylinder IIRC.
A speedometer
I tried the original 1408 speedometer with the output from the
LT230, and it just wasn't usable - 70mph arrived at about an
indicated 40mph, which meant where-ever I put stickers it wasn't
going to be possible to read it accurately enough to know how
fast I'm going. I've currently got a speedo from a Reliant
Rialto fitted, which appears to be about 960tpm, and which
under-reads by about 10%, which is close enough to allow me to
re-sticker the face with the right numbers...
Part 2 - "fitting the gearbox" coming shortly, but probably not
tonight. (I'll try and take some photos of my motor when its
daylight, showing the relevant bits).
Mods - I don't know if the editing time limit applies to this
thread - it would be helpful if it could be left so I can come
back an edit it, as doubtless as I write more stuff, I'll think
of things that would go better in earlier sections...
#Post#: 51482--------------------------------------------------
Re: 5 speed gearbox conversions (LT77/R380)
By: RMS Date: February 11, 2013, 2:54 am
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John,
Can you use a Disgay LT77S with a Defender (short) bellhousing
and input shaft?
Cheers,
Robin.
#Post#: 51905--------------------------------------------------
Re: 5 speed gearbox conversions (LT77/R380)
By: estwdjhn Date: February 15, 2013, 5:39 pm
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Part 2 - fitting the gearbox. (or, at least ramming it in the
gap, and stopping it falling on the road)
I had Bitsa over a pit last night (for reasons related to blown
up starter motors rather than gearboxes), so I've taken a few
photos to help show how the thing fits. Please remember it's a
high annual mileage motor, so it does just get covered in dirt
under there...
First off - a general view of what a LT77/LT230 looks like from
underneath, badly stitched together from a couple of photos.
HTML http://images.serieslandrover.co.uk/lt77tech/mounts5.jpg
As you can see, it all fits in the gap (just), but it doesn't
leave masses of room behind the handbrake. When I made the
gearbox mounts, I jacked the gearbox into place so the rear
propshaft exited more or less central through the hole in the
crossmember, and then measured up for the mounts to hold it
something like that. Talking of mounts...
HTML http://images.serieslandrover.co.uk/lt77tech/mounts1.jpg
HTML http://images.serieslandrover.co.uk/lt77tech/mounts3.jpg
The passenger side mount, looking from the back of the vehicle.
The bit bolted to the gearbox was a passenger side mount from a
300tdi/R380 disco, which I gassed off (other cutting methods are
available) in line with the top face of the rubber mount. The
"ear" that's welded to it was gassed out of a 200tdi disco
engine mount, and the whole lot welded up with a stiffener bar
to stop the "ear" bending back in service.
HTML http://images.serieslandrover.co.uk/lt77tech/mounts4.jpg
HTML http://images.serieslandrover.co.uk/lt77tech/mounts6.jpg
The drivers side mount is made from a 90/110 gearbox mount
(thats the pad bolted to the gearbox - it's only flat plate)
welded to the other ear cut from that disco block mount.
Both mounts are rather crudely finished, but do remember when I
did the deed it had to be back on the road inside 12 hours of
starting the job, which didn't leave a lot of time for
presentation work.
HTML http://images.serieslandrover.co.uk/lt77tech/mounts2.jpg
This shows my bell-housing crossmember with the front propshaft
fitted, with the suspension "at rest" about in the middle.
Because the gearbox output flange .... Fnarr Fnarr .... Fnarr
Fnarr is further back on an LT230 than on a series box (look at
that underneath photo above), the propshaft gets quite close to
the crossmember.
It works for me, but if I was fitting a 5 speed to a vehicle
without a scalloped crossmember I would probably weld a scallop
in (just get some suitable dia pipe, cut a hole and weld the
pipe in to get a neat looking scallop).
Other underneath details:
Handbrake
The photos above show a discovery type cable handbrake. You
don't want one of these - while it can be made to work with the
original lever, the cable underneath can't be got anywhere neat,
and looks bound to get caught off-road sooner or later. If you
must use one (I didn't know other types existed when I fitted
this box), then make a holder that lives bolted to the bracket
that used to hold the handbrake relay, and shorten the pull-link
from the handbrake lever that originally went to the relay, and
it will all work well enough. You can see the cable end bracket
in the "overall" photo if you look carefully.
A much better solution is to use a handbrake backplate from a
90/110 gearbox. Remove all the cable connections and bracketry
and wing them in the scrap-bin, and you end up with a pull type
expanded in about the same place as it is on the series drum.
All you need to do then is to lengthen the pull rod from the
original relay a bit, and it all works really nicely (I'll be
making this modification next time I've got the box out).
Speedo cable
HTML http://images.serieslandrover.co.uk/lt77tech/LT230speedo.jpg
I used a standard series speedo-cable to suit the speedometer
fitting I had. Don't use the flange .... Fnarr Fnarr .... Fnarr
Fnarr that bolts onto the series gearbox - slide that out of the
way, and there should be a clip like the one in this picture to
hold the end of the cable in place. (Luke - I've not forgotten I
need to try and find you one!) Some later 300tdi transferboxes
may have an electronic sender unit fitted here rather than a
cable - AFAIK the box underneath is the same, you just have to
remove the sensor first.
It's worth understanding a bit about how LT230 speedo drives
work - they use interchangable plastic output gears to turn the
speedo drive, and you can get gears with different numbers of
teeth to alter the TPM(turns per mile) figure. The gears are as
follows:
FRC3310 gear 20 teeth Blue
FRC 3311 gear 21 teeth Green
FRC3312 gear 22 teeth Yellow
FRC3313 gear 24 teeth Red
IIRC the input gear for these is a worm with 1 "tooth", so that
means the speedo cable turns once for every 20 turns of the
propshaft with blue gears etc.
Using this along with the diff ratio and tyre circumference
should allow you to calculate an accurate tpm figure.
Use this formula for imperial* tyres:
(63360/(Tyre size (e.g. 7.50)+Rim size (normally
16)/2)*3.142*diff ratio(e.g 3.54))/(speedogear teeth (eg 22))
Example:
(63360/(7.50+(16/2))*3.142*3.54)/(22) = 663tpm
Next part (no 3) will probably be about the fit inside the cab,
but that will have to wait for me to clear some junk out and
take some pictures...
*metric tyres are gay, and make maths really complex, so I'm not
going to try and write a formula for them at this time of night.
Edit - I'm not sure that that formula is right - and google
suggests that the worm is 5 start. I'll have to look through my
pile of scrap LT230 bits to find the truth, and run the maths
again when I'm more awake. *help*
#Post#: 51907--------------------------------------------------
Re: 5 speed gearbox conversions (LT77/R380)
By: Lightweight Nat Date: February 15, 2013, 6:58 pm
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John, just to clarify, is your gearbox crossmember still in the
original place it was in with an LT76?? This is really helpful
stuff, thanks. Looking forward to the bit about taking the guts
out of the LT230 centre diff to make it RWD only. :)
#Post#: 51909--------------------------------------------------
Re: 5 speed gearbox conversions (LT77/R380)
By: estwdjhn Date: February 16, 2013, 2:35 am
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[quote]John, just to clarify, is your gearbox crossmember still
in the original place it was in with an LT76??[/quote]
Gearbox crossmember is exactly as it left the factory. Mine is
removable, because I'm on an MOD chassis, but that shouldn't
make any difference to anything.
#Post#: 52180--------------------------------------------------
Re: 5 speed gearbox conversions (LT77/R380)
By: estwdjhn Date: February 18, 2013, 4:07 pm
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[quote]John,
Can you use a Disgay LT77S with a Defender (short) bellhousing
and input shaft?
Cheers,
Robin.
[/quote]
I think the short answer is - yes, under some circumstances.
The bad news comes in two parts:
1) Not all longstick input shafts are equal. My 1987 on defender
parts book lists a mere 5 part numbers, and I don't think that
includes any short-stick variants. Most broken longstick boxes
are type 50A (from 2.5 powered 90/110), and the inputs shafts
for those definitely don't match the one needed for the
longstick LT77s (56A).
2) The internal main selector bar is different between a
longstick and shortstick box, and the selector is about as
deeply embedded in the box as you can get. Just to add insult to
injury, the selector bar is also different between a 50A and 56A
box...
I'm currently working on a couple of possible solutions to these
problems (particularly the selector issue) - watch this space as
they say.
Incidentally, if anyone could point me to a range-rover or disco
parts book, to say it would be helpful is an understatement...
#Post#: 76107--------------------------------------------------
Re: 5 speed gearbox conversions (LT77/R380)
By: estwdjhn Date: September 29, 2013, 4:04 pm
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[quote author=estwdjhn link=topic=4660.msg52180#msg52180
date=1361225232]
I think the short answer is - yes, under some circumstances.
I'm currently working on a couple of possible solutions to these
problems (particularly the selector issue) - watch this space as
they say.
[/quote]
Sadly, research basically concluded that it's easier and cheaper
to just buy a box that works!
I will try and finish this guide at some point - it's basically
waiting for me to have the cab tidy enough to attempt some
pictures (yes, you're right - it may be a long wait!). Oh, and
it's also waiting for me to have a transfer box in bits to take
photos of that.
Oh, and while we wait, here is a chassis mod that I eventually
did to my 109" so as to get at the handbrake without taking the
gearbox out... (It's not such an issue with an 88" as I
recall). The crossmember has had the ends welded up and crush
tubes added for the bolts (I used M16x130). I'm not going to do
a full step by step guide - this pic is just to give ideas to
other inventive minds (who will probably then think of a better
way of doing the same thing!).
HTML http://images.serieslandrover.co.uk/crossm5.jpg
#Post#: 78023--------------------------------------------------
Re: 5 speed gearbox conversions (LT77/R380)
By: icedmunkie Date: October 23, 2013, 4:17 pm
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I will post some bits and pictures up of my conversion somepoint
too if you don't mind John?
#Post#: 78215--------------------------------------------------
Re: 5 speed gearbox conversions (LT77/R380)
By: estwdjhn Date: October 26, 2013, 4:50 pm
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Post away mate :smile1
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