L322 Does the L322 have a VCU ?

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awkwardbob

awkwardbob

Well-Known Member
Posts
578
Location
Glasgow
Having not learned my lesson with my P38, I’m looking at getting a seemingly inexpensive L322 to get me around until I can get the P38 (and my ‘boring’ car) back on the road.

Having been burned by the VCU in my P38 (which trashed both rear and then front diffs on the way out) I was wondering whether the L322 has a VCU in the transfer box ?

While I’ve read a few threads of checklists, other than water / oil leaks and EAS issues, is there anything else in particular I need to look out for ? (Aside from the eye-watering running costs)

Thanks !

Bob
 
Aye, you’re probably right but I don’t have the time I need to get the old girl through her MOT (need to do the front upper and lower ball joints, replace a seat loom and replace the leaky heater matrix ‘o’ rings) and the boring car is waiting on a part from Germany and needs the heater matrix replacing which the garage wants a horrific fee to remedy.

It’s a 2003, 2 owner 4.4. Seems to be broadly ‘honest’ and is only meant to be a short-term fix (I’ve some stuff to move around) after which I may wave it off on its merry way.

Is this madness ? -I kinda half think it is
 
The early 1s had a TB diff (torque bias) and the later was the electronic control late type

Not sure what year they changed 2002 manual shows the TB type 2007 manual shows the plate type.

If its only a temp fix I would consider some other brand or a pick or van, If you buy it you will like it and want to keep it ;) .

J
 
awkwardbob said:
Having not learned my lesson with my P38, I’m looking at getting a seemingly inexpensive L322 to get me around until I can get the P38 (and my ‘boring’ car) back on the road.

Having been burned by the VCU in my P38 (which trashed both rear and then front diffs on the way out) I was wondering whether the L322 has a VCU in the transfer box ?

While I’ve read a few threads of checklists, other than water / oil leaks and EAS issues, is there anything else in particular I need to look out for ? (Aside from the eye-watering running costs)

Thanks !

Bob
Click to expand...
Not sure I follow exactly. The p38 doesn't have a VCU in the same sense as the Freelander 1. It does use a viscous centre diff in the transfer box. What exactly has happened to it? I'd expect a viscous diff to normally fail to open, rather than locking solid. Although I don't think they are a known failure point and have been used in classic Range Rovers prior to the p38. It is also a popular transfer box for 80" CCV competition trials vehicles, so should be up to taking some punishment too.

Again, I'm a bit lost on the description of front/rear diffs on the way out???? They will either work, or be broken. There isn't really much in-between. How are you determining they are 'on the way out"?

As for the L322, which one? Early models (pre 2005) use BMW engines, the petrol V8 uses a Torsen style centre diff not a viscous one. The Td6 diesel uses a different gearbox and I'm unsure if the transfer box is also different but it might be the same. Post 2005 models use the Jaguar/Ford based engine range and use an electronically controlled clutch plate transfer box.
 
300bhp/ton said:
Not sure I follow exactly. The p38 doesn't have a VCU in the same sense as the Freelander 1. It does use a viscous centre diff in the transfer box. What exactly has happened to it? I'd expect a viscous diff to normally fail to open, rather than locking solid. Although I don't think they are a known failure point and have been used in classic Range Rovers prior to the p38.
Click to expand...

It is a problem, wouldn't say exactly common, but its there.

I will let you read this first

www.landyzone.co.uk

P38A - About that VCU thingy.

If both Freelander's AND P38's "benefit" from VCU's, how come I don't see large numbers of posts about seized P38 VCU's or One Wheel Up tests for P38's? Is it that the VCU plays a MAJOR part in a Freelander and a MINOR part in a P38? Not trying to be an AR5E, just not understanding the...
www.landyzone.co.uk www.landyzone.co.uk

J
 
300bhp/ton said:
Not sure I follow exactly. The p38 doesn't have a VCU in the same sense as the Freelander 1. It does use a viscous centre diff in the transfer box. What exactly has happened to it? I'd expect a viscous diff to normally fail to open, rather than locking solid. Although I don't think they are a known failure point and have been used in classic Range Rovers prior to the p38. It is also a popular transfer box for 80" CCV competition trials vehicles, so should be up to taking some punishment too.

Again, I'm a bit lost on the description of front/rear diffs on the way out???? They will either work, or be broken. There isn't really much in-between. How are you determining they are 'on the way out"?

As for the L322, which one? Early models (pre 2005) use BMW engines, the petrol V8 uses a Torsen style centre diff not a viscous one. The Td6 diesel uses a different gearbox and I'm unsure if the transfer box is also different but it might be the same. Post 2005 models use the Jaguar/Ford based engine range and use an electronically controlled clutch plate transfer box.
Click to expand...
Hi,

The viscous coupling in my P38's transfer box locked solid. The first consequence of this was the rear diff grinding itself apart whilst cruising at 70 in the middle lane of the motorway -it was not fun.

Replaced the destroyed rear diff and then felt something wrong with the front end (it felt like the power steering wasn't working) I now realise this was transmission wind-up caused by the seized (locked) VC and which, ultimately, destroyed the front diff too (now replaced).

So what I meant was that the VCU seized and took both diffs with it.

I was just asking whether the L322 had a similar system so that I knew to check it. The one I'm looking at is 2003 so has the TB version which seems to be mechanical rather than viscous.

Cheers

Bob
 
300bhp/ton said:
Not sure I follow exactly. The p38 doesn't have a VCU in the same sense as the Freelander 1. It does use a viscous centre diff in the transfer box. What exactly has happened to it? I'd expect a viscous diff to normally fail to open, rather than locking solid. Although I don't think they are a known failure point and have been used in classic Range Rovers prior to the p38. It is also a popular transfer box for 80" CCV competition trials vehicles, so should be up to taking some punishment too.

Again, I'm a bit lost on the description of front/rear diffs on the way out???? They will either work, or be broken. There isn't really much in-between. How are you determining they are 'on the way out"?

As for the L322, which one? Early models (pre 2005) use BMW engines, the petrol V8 uses a Torsen style centre diff not a viscous one. The Td6 diesel uses a different gearbox and I'm unsure if the transfer box is also different but it might be the same. Post 2005 models use the Jaguar/Ford based engine range and use an electronically controlled clutch plate transfer box.
Click to expand...
Sorry the P38 does not have a viscous diff in the transfer box, it has a conventional diff, the viscous coupling serves as a diff lock.
 
Datatek said:
Sorry the P38 does not have a viscous diff in the transfer box, it has a conventional diff, the viscous coupling serves as a diff lock.
Click to expand...
Nope. No such thing as a diff lock on the BW transfer box... hence no level for it like on an LT230. It is a viscous diff and is a form of limited slip differential. That will transmit power to both axles, yet still allow a difference in output shaft speeds f/r. It is fully mechanical and fully automatic in its operation.
 
300bhp/ton said:
Nope. No such thing as a diff lock on the BW transfer box... hence no level for it like on an LT230. It is a viscous diff and is a form of limited slip differential. That will transmit power to both axles, yet still allow a difference in output shaft speeds f/r. It is fully mechanical and fully automatic in its operation.
Click to expand...
I'll post photo's later, it's a normal diff, the viscous coupling sits across the front and rear output shafts an locks progressively if there is a speed differential.
 
VCU .. a potentially expensive device for locking the centre diff, originally conceived for the benefit of owners devoid of off-road driving experience or those that have but can't raise the energy to move a lever ;)
 
norseman said:
VCU .. a potentially expensive device for locking the centre diff, originally conceived for the benefit of owners devoid of off-road driving experience or those that have but can't raise the energy to move a lever ;)
Click to expand...
There are other advantages. You get benefits everywhere. Such as on road. Rally type cars like a Celica GT-Four or Impreza Turbo use centre limit slip diffs and aren't off roaders.

It also means the RRC/p38 is fully automatic as you switch surfaces, be it going from snow to tarmac, sand or wet grass fields. You can see LR tried do similar with the Discovery 2 and using traction control, but you are then fully reliant on the TCS working. And as many know, a D2 with non functional TCS will get stuck on the first bump or rut off road.

As a side effect you'll also get a better turning circle with the BW transfer box vs a locked LT230 when off road. Which is handy in general and hugely beneficial for trialling.
 
norseman said:
VCU .. a potentially expensive device for locking the centre diff, originally conceived for the benefit of owners devoid of off-road driving experience or those that have but can't raise the energy to move a lever ;)
Click to expand...
And saving the destruction of the centre diff via wheel spin
 
They seem very clever and great, right up until the point they seize and trash your transmission !

If, god forbid, I ever buy another P38
I’ll be sure to check the VCU -although I’m more committed to getting / keeping mine in good Nick for now.
 
300bhp/ton said:
There are other advantages. You get benefits everywhere. Such as on road. Rally type cars like a Celica GT-Four or Impreza Turbo use centre limit slip diffs and aren't off roaders.

It also means the RRC/p38 is fully automatic as you switch surfaces, be it going from snow to tarmac, sand or wet grass fields. You can see LR tried do similar with the Discovery 2 and using traction control, but you are then fully reliant on the TCS working. And as many know, a D2 with non functional TCS will get stuck on the first bump or rut off road.

As a side effect you'll also get a better turning circle with the BW transfer box vs a locked LT230 when off road. Which is handy in general and hugely beneficial for trialling.
Click to expand...
The trouble with the P38 VCU is it requires loss of traction at one end of the other before it decides to lock whereas a centre diff lock properly applied is used to prevent or reduce loss of traction in the first place.
 
Datatek said:
The trouble with the P38 VCU is it requires loss of traction at one end of the other before it decides to lock whereas a centre diff lock properly applied is used to prevent or reduce loss of traction in the first place.
Click to expand...
For the avoidance of doubt, here is a drawing of the P38 centre diff with explanation of where the VCU is fitted.
Centre diff001.jpg
 
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