Diff locks - old and new types - which is best?

[Dr Strangeglove]

The older classic Rangies have a lever to engage diff lock with the later classics doing it automatically.  What is the difference?  Is one better than the other and do they have any faults??

[Skibum346]

The later RRC's use a borg warner transfer box that has a viscous coupling. The coupling locks up if one axle turns faster than the other (not a very accurate description but you ge the jist). One issue with this is that as it ages, the viscous coupling can deterirate and sieze meaning your driving around with difflock in on the old black stuff... causing untold damage to tyres and causing transmission wind up.

The older versions do exactly tha same job but the job of the viscous coupling is done by the MkI driver and the transfer lever. As the MkI driver ages it deterirates and often forgets to engage or disengage the difflock... causing untold hilarity to all those in the area!  :lol:

As to which is best... depends how old the driver is!  :(biglaugh):

[Range Rover Blues]

When it works the viscous coupling is a great thing, given the market place of the Range Rover when new.  Because it's there all the time you get better stability on greasy roundabouts where the older cars used to understeer, if any thing you get a tiny amount of oversteer as the back end will step out as far as the front but no further, so it's safer to drive on a day like today.

As mentioned when the units get old the thermo-vicous fluid goes hard and can lock the unit up solid.  CVs suffer and soon fail.

THe old LT230 is an open diff transfer box, it's either in or out, no limited slip at all.  Where is does score is that when it's in, it's in.  The B-W has to have a relative movement to heat the thermo-vicous fluid and so lock the diff, so when you park up on a slippery surface the front wheels will slowly turn, this has caused me problems in the past, had the B-W got a mechanical lock as well it would be the dogs bits, but it doesn't.  For this reason I'm considering sacrificing on-road handling for off-road ability.

[Henry Webster]

Because it's there all the time you get better stability on greasy roundabouts where the older cars used to understeer, if any thing you get a tiny amount of oversteer as the back end will step out as far as the front but no further, so it's safer to drive on a day like today.

I hadn't driven my 'road' Discovery (LT230) in slippery conditions for a while until this morning.  I'd forgotten how marked the difference was. Understeer city - with or without the diff in!   :shock:

With a limited slip diff in the rear as well as the BW the racer is emminently chuckable.  Oversteer is its favourite guise, but not too much!

Suffice to say I was thinking about putting one in the 'road' discovery, only I don't spose I'll get around to it! :roll:

[barnhill4x4]

I have today driven both the Disco on Machos and the P38 on road tyres.
  THe disco is understeer mad, I was left foot braking to control it better. THe P38, oversteer heaven!
   The p38 is alot easier to drive on snow than the disco, a different story off road though

[Difflock]

How can you tell then if the viscous type diff lock is sh***ed,had mine (1992 Turbo D) jacked up in work Today so I could sort a power stearing pump leak out and thought I would see if it would drive forward with just the rear wheels on the ground as its only got the high and low lever,it moved  :shock:  :shock:  does that mean its seized and can you repair it if it is    

[Range Rover Blues]

With a handle like Difflock I'd have thought you'd know

The thermo-viscouos fluid thickens when slipping occurs but is always stiff, so although you might be able to slowly turn one prop by hand, as soon as you try to drive the car the stuff locks up, it will slip just enough to release the wind-up.  I find I can just turn the handbrake drum very slowly, I can tighten a propshaft nut up against the viscous hub, or remove a wheel nut even :shock: .  You should be able to turn one wheel VERY slowly with it jacked up.

[Difflock]

Difflock only in name Iam affraid my friend but give me a couple more weeks tinkering and I'll have it sussed    

[Range Rover Blues]

Ok, well with one wheel jacked up you should be able to turn that wheel slowly, especially if youuse the nut wrench for leverage.  If the viscous unit is goosed it can be swapped in situ by removing the front end of the transfer box, it's not half the weight of the T-box but still heavy.

[Skibum346]

How can you tell then if the viscous type diff lock is sh***ed,had mine (1992 Turbo D) jacked up in work Today so I could sort a power stearing pump leak out and thought I would see if it would drive forward with just the rear wheels on the ground as its only got the high and low lever,it moved  :shock:  :shock:  does that mean its seized and can you repair it if it is    

Big diagnosis point is scrubbing of the front wheels on full lock. Try turning tight circles with it and if you can hear scrabbling from the front this is an indicator.

Skibum

[Range Rover Blues]

Yes very true, as is chronic understeer on a loose surface (hang on, mine does that :? ).

[Skibum346]

Yes very true, as is chronic understeer on a loose surface (hang on, mine does that :? ).

Mustmean your using too much right pedal!!!   :lol:

[Range Rover Blues]

The LSE suffers worse becasue of the extra length, and the big V8 really doens't help things :roll:

[Skibum346]

The LSE suffers worse becasue of the extra length, and the big V8 really doens't help things :roll:

Nothing to do with the V8... it's the size 8 that's the problem!!!

**Peers guiltily around the room looking for an exit asI'm as guilty!!**

[Range Rover Blues]

Nothing to do with the V8... it's the size 8 that's the problem!!!

5.0l TVR/Rover V8 :o

[Skibum346]

Nothing to do with the V8... it's the size 8 that's the problem!!!

5.0l TVR/Rover V8 :o

Ah...
So...
I rest my case!!!!!!   :lol:

[Range Rover Blues]

Yes, after all I have checked the Viscous unit already.