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Discussion Starter · #1 ·
Okay, I'd like to sort this out.

Is there any performance benefit, or loss with the viscous coupling transfer case that was used from 89 on, rather than the 87 and 88 which you locked the center dif manually? By performance I mean off road traction, as well as general road performance.

I've been wondering things for a while,and wondering if anyone knows a the actual answer to it.

Thanks.
 

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Viscous Couplings.....

Hi Devon,
I have played with both types & I have found them to be equally as good as each other.
I prefer the later one as its one less thing to worry about when your in the thick-of-it! They have proven to be very solid units & rarely fail.
Anyone out there have one fail?

Thats my 2 cents....

Andy :)
 

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THE MAIN FUNCTION OF THE VISCOUS COUPLER IS TO LIMIT THE MAXIMUM DIFFERENCE IN SPEED BETWEEN THE TWO DRIVE SHAFTS (FRONT & REAR) DOING SO BY LOCKING THE DIFFERENTIAL, ALSO HELPS WITH CIRCLE TURNING THEN THE CERICLE TURNS A CIRCLE ALL FOUR WHELLS TRAVEL THOUGHT FOUR DIFFERT ARCS, AND ALL FOUR WHEELS TRAVEL AT FOUR DIFFERENT SPEEDS, THE MAIN DISADVANTAGE IS THAT IF ONE WHEEL LOOSES TRACTION ALL OF THE POWER WILL GO TO THE WHELL THAT IS SPINING AND THE OTHERS WILL NOT TURN, THATS WHEN THE DIFF LOCK COMES IN HANDY! HOPE THIS HELPS, THERE SHOULD BE NO DISADVANTAGE TO THE VISCOUS COUPLING SET-UP. :drive:
 

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Discussion Starter · #4 ·
LRR219 said:
THE MAIN DISADVANTAGE IS THAT IF ONE WHEEL LOOSES TRACTION ALL OF THE POWER WILL GO TO THE WHELL THAT IS SPININ AND THE OTHERS WILL NOT TURN, THATS WHEN THE DIFF LOCK COMES IN HANDY! HOPE THIS HELPS, THERE SHOULD BE NO DISADVANTAGE TO THE VISCOUS COUPLING SET-UP. :drive:
When you are off road, it seems that this would be a big problem. Is this not so on the non viscous copuling transfer cases, like the 88 and 87 range rovers had? If so, in mud or slippery surface, wouldn't the non viscous coupling prevail over the viscous coupling? I also wondered why Land Rover would've changed something like that, if it made it perform worse.
 

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The VC goes through varying degrees of lockup, as opposed to the LT 230 which either locked or open. It reacts fairly quickly, only a few revs of missmatched driveshaft speeds, so the arguement that you get stuck before it locks isn't valid. If you got stuck, you were going to, Borg Warner or LT230.
By definition, if one wheel started spinning, then both wheels of the other axle were not spinning. Some power would be going to that axle (The VC wouldn't be unlocked if there was a whell spinning) so you're going to maintain some forward motion.
Yes, they do fail but the VC unit is available seperately, you don't have to change out the whole case, though if it's old enough to fail, chances are pretty good your chain is howling pretty good by now and is pretty well stretched.
 

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LRR219 said:
THE MAIN FUNCTION OF THE VISCOUS COUPLER IS TO LIMIT THE MAXIMUM DIFFERENCE IN SPEED BETWEEN THE TWO DRIVE SHAFTS (FRONT & REAR) DOING SO BY LOCKING THE DIFFERENTIAL, ALSO HELPS WITH CIRCLE TURNING THEN THE CEHICLE TURNS A CIRCLE ALL FOUR WHELLS TRAVEL THOUGHT FOUR DIFFERT ARCS, AND ALL FOUR WHEELS TRAVEL AT FOUR DIFFERENT SPEEDS, THE MAIN DISADVANTAGE IS THAT IF ONE WHEEL LOOSES TRACTION ALL OF THE POWER WILL GO TO THE WHELL THAT IS SPININ AND THE OTHERS WILL NOT TURN, THATS WHEN THE DIFF LOCK COMES IN HANDY! HOPE THIS HELPS, THERE SHOULD BE NO DISADVANTAGE TO THE VISCOUS COUPLING SET-UP. :drive:
That is the whole point of the viscous coupling, to deliver torque to both axles when needed. On the road, it is aloud to slip, but when the slippage becomes too great, it will lock the axles together. The whole idea is to have an automatic CDL so you don't have to worry about it. It essentially does the exact same thing.
 

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well you did a little contradicting in the end...

THE MAIN DISADVANTAGE IS THAT IF ONE WHEEL LOOSES TRACTION ALL OF THE POWER WILL GO TO THE WHELL THAT IS SPININ AND THE OTHERS WILL NOT TURN, THATS WHEN THE DIFF LOCK COMES IN HANDY!
but in the beginning that's what you said. :) . sorry. just wanted to make sure it was clear.
 
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