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Speedo drive after BW -> LT230 conversion


Bowie69
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I have recently finished the conversion from a BW transfer box to an refurbed 1.410 ratio LT230 in my 1991 Range Rover, this has all gone pretty smoothly, until after a road test (a fast one!   :lol:) I have found the speedo isn't working.

I have had a look at the cable which links to the transducer bolted to the chassis, and it appears OK, not what I would call worn for sure, both ends look the same, and twist one end and the other spins freely :)

The mechanics of the transducer seem OK, insert cable, twist and there is some definite extra friction, so I can assume that side is OK, though I have not checked the electronics side.

That just leaves the transfer box speedo drive I believe...? if I shove the cable into the speedo drive I am able to spin the cable easily with my fingers, it's not making any purchase at all it seems? 

Jack up one wheel, handbrake off, in neutral and I can see and feel the speedo drive rotating quite happily in the housing.

So two things I guess could be the culprit, one is a worn speedo cable (it's still square, and fits and operates the transducer on either end) or the actual speedo drive is worn out or possibly the wrong part? I tried levering the speedo drive out of the housing, with no joy, although the one on the now spare BW box popped out fine, is there anything holding them in other than an o-ring?

Replacement T-box is a suffix C box, from (I think) and 89 90 TD.

Quick pic of the speedo cable:

post-4193-127072403447_thumb.jpg

Thanks for any help :)

Bowie.

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Ah nevermind, got it sorted.... It seems the 90/LT230 drive has a larger square in it than the RRC one, and after much swearing I got the LT230 drive out and managed to swap the gear from the BW box and speedo now works... :)

Might be useful for someone else though :)

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Ah nevermind, got it sorted.... It seems the 90/LT230 drive has a larger square in it than the RRC one, and after much swearing I got the LT230 drive out and managed to swap the gear from the BW box and speedo now works... :)

Might be useful for someone else though :)

I'm going to make the same swap in a few weeks, so Thx.

Any other good links to how make the swap of the TC itself? Or is it al just as simple as it looks?

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TBH, it's nuts and bolts, only issue you may come up with is the output shaft not having long enough splines on it if the TC has been updated to a cross-drilled input gear.

Couple of other points.....

I used a transfer lever from a V8 disco which fitted perfectly, although did need a fair bit of adjustment to get the difflock throw right, and it is really tight in there, so try and do it whilst the box is still lowered a bit, and you haven't fitted the hand brake.

I didn't use the drum handbrake, as I had an X-brake waiting on the shelf to go on, but I do know the BW and LT ones are not interchangeable without re-drilling the backplate and possibly the handbrake cable won't fit.

You need a different mounting bracket from the TC to the rubber doughnut, but the chassis half can remain the same. Change doughnut at the same time....

Disco 1 300TDi front prop replaces the BW front prop, Gwyn Lewis part number GL637 is ideal, wide angle and heavy duty :)

REMOVE THE EXHAUST MIDDLE BOX! I dropped mine just to the ground (no rear box) and whilst is was kinda out of the way, I did keep smacking my head on it.

If you are going X-brake, I had to shorten the lower of the two spacers by 5mm as the head of the bolt was knocking on the middle box (quite noisy). You will defo need to shorted the caliper lever as well.

Oh, and did I mention, P38 4.0 with Kent H200 cam, Rhoads lifters and ported heads, coupled to a nice 1.410 ratio TC  and 33" Simex JT2s makes for an impressively speedy drive  :lol:

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  • 8 months later...

bowie69,

I've been reading your posts on this conversion with interest as i want to do the same on my 94 classic.I seem to have lost the locking up of the viscous coupling and would like to bin the borg warner for an lt230. If i get a 1.4 ratio also it would help my gearing in high box for the 35" tyres i've got.

Mine is an auto and if i get the lt230 from a defender , what input shaft will i need ? And does it simply pull out of the rear of the autobox? Also,can i use any discovery linkage or does it have to be from an auto.If so can a diesel auto linkage be used or must it be a v8 one ?

Lastly, you say that a different length prop must be used on the front. And it looks like your using a diesel one,aren't the v8 ones solid,therefore smaller diameter so won't the diesel type one hit the front gearbox crossmember ?

I've been scratching my head with this lot so your help would be great.My rangie is a bit poor with an open centre diff in this snowy weather !

cheers,

andy

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Hmmmmm, at last a thread on almost what i want to do, its just backwards.

I'm looking at changing the LT230 in my lightweight to a viscous transfer box.

So I just have a few questions:

-Overall transfer box size, is there a major difference between the two? I currently only have about an inch clearance between handbrake drum and crossmember behind gearbox (nightmare when doing handbrake shoes, gearbox has to be dropped)

-Front prop difference, which box uses a longer prop? Thinking of engine crossmember clearance issues (will be making another crossmember when I finally get round to doing twin downpipe exhaust mod but would be nice to be able to leave that for another day)

-Gearbox mounts, i currently have the defender type mounts that bolt to the chassis, rangie uses a 2 big rubber block type mount on the crossmember under the gearbox? Will i be able to swap my current mounts onto the BW t'box?

-And as for speedo drive, its just a case of swapping my existing 90 gear into the rrc BW box?

I will have to look into ratios, im guessing theres difference BW ratios or are they all the same?

Did any defenders have the BW t'box fitted as standard?

Think thats everything i wanted to ask,

Al

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bowie69,

I've been reading your posts on this conversion with interest as i want to do the same on my 94 classic.I seem to have lost the locking up of the viscous coupling and would like to bin the borg warner for an lt230. If i get a 1.4 ratio also it would help my gearing in high box for the 35" tyres i've got.

Mine is an auto and if i get the lt230 from a defender , what input shaft will i need ? And does it simply pull out of the rear of the autobox? Also,can i use any discovery linkage or does it have to be from an auto.If so can a diesel auto linkage be used or must it be a v8 one ?

Lastly, you say that a different length prop must be used on the front. And it looks like your using a diesel one,aren't the v8 ones solid,therefore smaller diameter so won't the diesel type one hit the front gearbox crossmember ?

I've been scratching my head with this lot so your help would be great.My rangie is a bit poor with an open centre diff in this snowy weather !

cheers,

andy

Hi Andy, sorry for not replying earlier, I missed your post!

1.4 would be OK with your 35" tyres, but I would be tempted to look for a 1.66 ratio box, it would bring you much closer to stock, if my calcs are correct, even so, a 1.4 will be a huge improvement for sure.

The autobox output shaft is held on with 1 long bolt in the end of it, very easy to swap if needed. You only need to swap the output shaft if either your transfer case has the cross-drilled input gear, or the existing one is worn. If you do need to replace, ring Ashcrofts, he'll have them on the shelf.

I am not sure what the difference, if any, there is between diesel/V8 disco linkage, I suspect they are identical, just giving you the info which worked for mine, which was a 200 series V8 disco :)

As for the props.... yes it's a diesel one, the very late V8 classic ones were slimmer, however mine wasn't, being a 1991, it's not ap roblem however, as the distance between the output flanges of an LT230 is greater than a BW, meaning you need a shorter front prop, meaning it clears the crossmember more easily. :)

Lastly, you say you have lost the viscous coupleing, and it is open... are you sure? They normally fail in a locked situation.... It sounds like you may have just broken a halfshaft...... would be worth checking, quite easy, I'd drop the front prop off, and see if it drives still, replace, then drop the rear prop off and see if it drives..

HTH :)

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Hmmmmm, at last a thread on almost what i want to do, its just backwards.

I'm looking at changing the LT230 in my lightweight to a viscous transfer box.

So I just have a few questions:

-Overall transfer box size, is there a major difference between the two? I currently only have about an inch clearance between handbrake drum and crossmember behind gearbox (nightmare when doing handbrake shoes, gearbox has to be dropped)

-Front prop difference, which box uses a longer prop? Thinking of engine crossmember clearance issues (will be making another crossmember when I finally get round to doing twin downpipe exhaust mod but would be nice to be able to leave that for another day)

-Gearbox mounts, i currently have the defender type mounts that bolt to the chassis, rangie uses a 2 big rubber block type mount on the crossmember under the gearbox? Will i be able to swap my current mounts onto the BW t'box?

-And as for speedo drive, its just a case of swapping my existing 90 gear into the rrc BW box?

I will have to look into ratios, im guessing theres difference BW ratios or are they all the same?

Did any defenders have the BW t'box fitted as standard?

Think thats everything i wanted to ask,

Al

No real difference in size, LT230 is larger between the output flanges, BW is deeper to the rear/left, meaning you can't fit an X-brake.

BW box uses the longer prop, and are scarily expensive new, fortunately the breakers round here don't know that ;) I suspect you will have issues with the crossmember, I think the difference is ~ 50mm in length, I don't think Gwyn Lewis does these in wide angle either, you may need to get one made up specially.

Gear box mounts.... Well, the transfer box mount is the important one, it's different, it sounds like to me you have the TD5 setup at the moment.... with square blocks of rubber? TBH, I would go get a full set from a Rangie and bolt that lot in, but you could maybe get away with just changing the transfer box mount.

Yep, just swap your LT230 gear into the BW, then go and calibrate to GPS or similar :)

All BW boxes are 1.2, great for cruising with a V8, not so great with a stinky diesel and large tyres... Someone does make a chain drive conversion to drop the ratio nicely for 33-35" tyres, but it is ~ £600 or thereabouts, which was out of my budget really.

AFAIK, no Defenders came with the BW box as standard, only the late RRC ('88 onwards I think).

:)

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1.4 would be OK with your 35" tyres, but I would be tempted to look for a 1.66 ratio box, it would bring you much closer to stock, if my calcs are correct, even so, a 1.4 will be a huge improvement for sure.

Ive got a LT230 1.66 ratio out of a 110 if its of any use ;)

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Bowie is right, only the RRC came with the BORDG-WARNER and then the P38 had a very similar box but the propshaft run the other side of the engine. All B-W are about 1:1.202, slightly higher than the LT230 in a Disco. The RRC at the time had a bit bogger V8 but also had the 300TDi and TBH it's absolutley fine (though the Disco had a slightly higher maximum weight)

On the road the B_W is much better but off it it's a pain sometimes. I want to swap for a LT230 too but need to sort the tinworm first.

AFAIK the LT230 is shorter, the front flange sits further back. I'm not yet sure if the TDi box sits in the same place as the V8 but it has a hollow propshaft unlike the V8. I think on the Auto there is less than an inch of difference between V8 and TDi but I never measured it.

On mine I fitted a TD5 flange and front prop which I had modified to suite, that works really well as I have a lift and castor correction so a wide-angle prop was not really the answer.

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Hi bowie69,

Thanks very much for that, i'm going to get all the bits together and try and do the swap in one go.

The halfshafts are ok . I was limping home in rear drive after blowing the front diff, then lost drive to the rear.I could hear a highspeed metallic noise in the gearbox area.After fitting a new front diff, it drives ok , but stuggles off road. I tried spinning the wheels up on ice and sometimes the rear axle would spin and sometimes the front.If i held the brakes on then gassed it , sometimes all 4 wheels would spin, but most of the time not su i assume the coupling is shot, i'm not sure.I'd prefer the lt230 anyway.

Thanks again,

andy

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