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o_teunico

Locking a VCU

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Hi all,

Let´s imagine that we want to adapt a Range Rover P38 Borg Warner transer case to a single driven axle aplication.

How could we lock the viscous unit? Will it "fail" (got fixed in this case) by simply leting it do it´s work?

Disasemble and weld maybe?

Thanks.

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Since they fail locked, I'd be inclined just to run it until it completely locks (which won't take long).  You could weld one up - but I wouldn't bother unless you really need to.

Si

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Being difficult about it I'd use a LT230 instead as that can be locked as standard, and/or you could weld the centre diff up and/or you could do the 2WD conversion on it.

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I seem to remember the BW box always drives the rear wheels no matter what, just allows slip to the front if necessary.... So should be fine straight away?

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1 minute ago, Bowie69 said:

I seem to remember the BW box always drives the rear wheels no matter what, just allows slip to the front if necessary.... So should be fine straight away?

That's my understanding too - I thought it is configured like an LT230 with a limited slip diff rather than locking diff.

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4 hours ago, Snagger said:

That's my understanding too - I thought it is configured like an LT230 with a limited slip diff rather than locking diff.

That's correct - but the limited slip is a viscose coupling (like on a Freelander).  I thought it drove the front wheels preferentially - but I could very easily be wrong.  If it drives the rear - then you have nothing to worry about!

Si

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The BW diff is in the front cover, ahead of the chain and sprockets.  The viscous unit itself is inside the diff, like the clutch packs on older LSDs.    The diff is essentially locked but can slip enough for the axles to separate, but the rear axle will be locked to the drive at all times.  The rati change is by an epicylcic unit behind the input shaft, so is done before the chain is driven.  The sprocket on the output shaft is directly attached to the rear oiutput and the back of the diff.

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Indeed, and driving with no front prop worked fine for me.

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2 hours ago, Snagger said:

  The diff is essentially locked  The sprocket on the output shaft is directly attached to the rear oiutput and the back of the diff.

Hi, 

not really, the diff is only locked if the viscous coupling has siezed, the rear is not locked to the drive constantly.

think of it as the same as the LT230 in terms of it having a centre diff but instead of manually locking it, the VC does this by limiting the amount the diff can differentiate ie only allows a low speed difference in the diff side gears, (propshafts)

Dave

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4 hours ago, simonr said:

If it drives the rear - then you have nothing to worry about!

Errrr...it was going to be the front prop the one giving the power...

I will explain why I´m thinking about this idea,

I want a to fit a BMW/OPEL/Range Rover six pot turbodiesel to my 88". SOA + lift (about 8" total) and long travel shocks are also in the agenda.

First idea was a simple setup: R380 with LT230, but a P38 R380 will not fit the LT230.

As Dave explained in another thread/forum, a K/L suffix Disco II box with rangie bellhousing and shaft will work, but that means that I will have to buy two boxes, and I´m working with a very limited budget.

And here my (vapour) solution, giving lot of advantages: absolutelly standard P38 R380+BW, no rear driveshaft and the front one...driving a divorced LT230, beeing fed by the PTO and clocked for beeing vertical. I already have a 4x2 Santana LT230, so just one box to buy. BW used as a doubler.

This setup will have driveshafts offset to the left. 110 rear Salisbury fitted upside down will have left side diff and "high pinion". Jeep Grand Cherokee ZJ front Dana 30 is left diff, high pinion, similar track to LR coiler axle and, that from 4.0 autobox, is 3.55 ratio. Not particulary strong, but a guy at the local club has managed to run 37" tyres with no breakages. Also "J" type steering linkage will suit the TRW (ex Nissan Cabstar) steering box.

This setup should end give front and rear propshafts a horizontal position and equal length. That should made unnecesary the neef of (not cheap) high angle shafts.

Left diff means right hand engine offset, anothe advantage for LHD cars, giving more room for the drivers foot.

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I'm sorry, but that just sounds ridiculous!

It won't fit length-wise, and you'd have such a non-standard running gear that is anything went wrong you'd be stuffed.

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What Bowie said, that sounds like a mad setup and I'm not even sure what you think the result is going to be good for? Can you explain what you're trying to achieve with all this?

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8" lift with all that heavy stuff up there...  It'll roll just parking on the kerb! ;)

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88 is too short for typicall Us rock crawling doubler setup. 

Everything absolutely standard, except the LT230 divorce. Standard components, differently located.

Divorced LT230 could be placed anywere you need, so no lengthwise problems, silly propshaft angles and so on.

Air suspension with high panhard should minimize body roll. Wider axles maintain heigth to width ratio as standard.

 

FB_IMG_1477759012723.jpg

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O´Téunico - I like it!  The people I have the most respect for are the ones who experiment & try 'crazy' stuff out.  It might work - it might not but the only way to find out is to build it.  God knows, I've had enough failures but they have lead to successes.

I've always wanted to try a divorced transfer box.  It has the potential to solve a lot of space problems.  My Suzuki had twin transfer boxes - and the Super low range was amazing.  Top speed of 4mph in 1st, Low, Low - with enough torque to break Toyota 80 axles (but not with Longfields).

Si

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Divorcing is the way! No adaptors needed, just a custom cheap mini propshaft.

Imagine that the transfer on the left is the BW 4462 from a P38, and the one in the right an LT230. Fit the PTO and "feed" it with the front axle propshaft from the 4462 and you will have the LT exactly in the middle of front and rear axles. 

IMG_0137.jpg

Edited by o_teunico
Wrong data
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...and use high panhard bar: no body roll with tons of travel. Yes, axle panhard mount will protrude into the rear tub in full compression. just make a hole in floor!

SATR315.jpg

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18 hours ago, o_teunico said:

88 is too short for typicall Us rock crawling doubler setup. 

Everything absolutely standard, except the LT230 divorce. Standard components, differently located.

Divorced LT230 could be placed anywere you need, so no lengthwise problems, silly propshaft angles and so on.

Air suspension with high panhard should minimize body roll. Wider axles maintain heigth to width ratio as standard.

 

FB_IMG_1477759012723.jpg

Wow! I see someone has taken my Redneck solution to a more pro level! :D 

WP_20140524_001.thumb.jpg.28b6d1a7452fb0a1eb97ca4ca3ea3706.jpg

 

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I will use airbags from p38 and leave the leaf springs in one piece, simply removing shackles. That way, in case of air suspension failure, it will just take a few minutes to go again on leafs.  

Airbags in front of axle will also give softer ride plus more travel. 

Transit leafs with orbit eye bushing could handle all that axle twist. 

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I don't think that'll work well - you won't need much articulation for the rear end of the springs to hit the chassis and possibly bind or catch on the shackle hanger.

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A slider bolted to the chassis hanger will avoid it from beeing catched. Once half of the compression travel is achieved, the leaf will touch the slider and start working as in a leaf suspension, making the air supension stiffer and softening the "landing" on the bumpstops.

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Here you see how Santana parabolics with no load are just touching chassis hangers. There are a pair of 4" blocks between axle and bumpstops in this picture.

post-48509-0-61873300-1395534437.jpg

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