picked up VCU today

It's good to see the rear wheels turn straight away. This proves there's drive to the rear wheels. However, it doesn't prove how much potential force the vcu can force into the rear wheels. If you imagine you can quantify the force of resistance across the vcu from 0 (no force and open circuit) to 100% (seized solid or activated fully due to differing speeds or props) and then apply this to what you see in the video, then a vcu with say 20% drive may turn the wheels when free in the air. If the same 20% vcu were used with all 4 wheels on the ground there may not be enough resistance across the vcu to drive the wheels. Where as a vcu with say 60+ drive could easily power the rear wheel on and off the ground. Bit confusing but it's difficult to explain.

A clearer way to test the vcu is with the one wheel up test. That gives us a comparable result to others, while under test conditions. It's shows the vcu isn't permanently seized and has a certain resistance of drive (1 prop turning and the other prop stationary). The best test you can do is the original wheel spinning you did on a slippery surface. Ideally with the front wheels being a on a more slippery surface than the rears, which would mean any forward momentum would be due to the rear wheels powering the car. Hence the vcu was passing the force to apply that power. And then proving afterwards the vcu isn't seized solid with the one wheel up test.

the one wheel test i did the other day and the weight of the breaker bar turned the wheel with no extra weight

matt1295 said:

the one wheel test i did the other day and the weight of the breaker bar turned the wheel with no extra weight

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how quick did it turn 45 degrees to the horizontal?

The problem we have is not enough people do the test so we don't have much of an average result. We have results from reconditioned units at 3 seconds to brand new one at 25 seconds. Most results are in-between.

i will go out tomorrow wheel test it again and time it and get back to you will do everything i can to save money lol and to no it works a little is better than nothing just need to find something in the house to use for weight as i aint taking my gym to bits for the 5kg weight lol

went out this morning got a bar 1.2m 5kg weight

so jacked wheel up put bar on rear hub nut i do have a video but didnt see the point it took 2 seconds to travel 90degree

Sounds as if it is fecked. But safe.

Need to start saving or selling a kidney unless anyone wants to buy a wife great cook great cleaner but a nagger well ain't they all lol

Is the welding as smooth as this one? Original vcu's are welded by machine. If it's been tampered with then the options are to cut it open, removed 1 or more plates and re-weld. Or open the 2 small fill holes (1 in the left of the vcu in the photo and another on the other side) to try to force some of the fluid out. Both options will reduce the effectiveness of the vcu. As MTM says your lucky in the fact the vcu seems to be less resistant as opposed to the worst case when it's more resistant and increases the stress in your transmission.



The 2 seconds turn isn't as bad as some I've seen, but it is quick. Others which have been tampered with drop like a stone as if the prop is missing. We can't confirm yours is one of these but it is turning much quicker than the average vcu. It would be nice to know if some of the plates inside were missing but that is often in conjunction with a noticeable re-weld. The big problem is we don't have enough results from original vcu's to know with some practical authority how a good one would perform. Some years ago when our testing started, 2006 Freelander 1's were less than 4 years old, so ideal for testing to collect date on reasonably new vcu's with some on low miles. Theory being we would find an average datum to work to. My vcu failed at 34.5k miles at 11 years old which throws a spanner in some theory's. GKN the original manufacturer knows the design spec as it's their design and I would assume LR does too, but keep the secrete private. To our knowledge GKN has never allowed third party companies to produce or recondition vcu's on their behalf, with or without the secrete knowledge of what the secrete is. They could easily allow someone to have that secrete knowledge under license and allow them to use it recondition them on their behalf under contract or to operate themselves independently, with some incentive to GKN as reward (£). Their business their choice. They make them new so it's kind of a good idea to keep selling new vcu's and I can appreciate this. Hence know one knows the exact chemical mix used (the exact chemical version, it's reaction time or critical point of activation, viscosity of the liquid, the ratio of liquid to air etc) so we have to work on what we have. Reconditioners have used trial and error to come up with their preferred mix. Some just put less liquid in which means the vcu activates later than normal. In theory thats a good thing. Our results would suggest 2 seconds is much quicker than most vcu's but the fact that your video shows you have power to the rear wheels when it was on mud means the vcu is activating and passing power to the rear wheels, which is what the vcu should do. It's just the case it's a bit looser than normal. So it's not as bad as it would at first seem. The one wheel up test isn't the best test available, but it's probably the best test we have. A constant torque across the vcu whilst measuring it's performance over time is the ideal way. This is way off what we can do ourselves as it involved machinery and monitoring to ensure correct test conditions, but it would be the ultimate test to see how the vcu performs under constant use, as if it were being used in real life operation.

If your vcu was mine then I'd be very very tempted to keep using it. Test it every so often to see how it's performing. If it's going to freeze overnight then tip some water on the long drive to your private country estate, where it's safe to do so, and use the ice to test it. Get the wheels spinning and film it to see how quickly it happens. Also try it with front wheels on ice and rears not on ice. The quicker it starts to push you forward, the quicker the vcu is activating.

Thanks guys. im going to leave it on and test it every other sunday to see if the time starts to take longer

im going to have to save to get the VCU so rather than having a propshaft sat in the house gives me the time to do some fortnightly tests

MTM and Hippo you are legends for all the info. but as soon as i get the money i may just replace it as i was wanting to do some greenlaning this year but im not sure if i would trust this VCU lol

also i will try and get some pictures of the VCU on to see what you think about the look of it but only if i can fit under the car without jacking it up lol

heres my VCU

I've just been thinking about this again and what we actually want to know from your vcu is how it performs under pressure. Wheels in the air turning proves it's powering the back wheels but they're running free wil little resistance. If the rear wheels had a lot more traction/resistance like the ice testing mentioned above then this would be a good test to see if the vcu can still power the rear wheels as opposed to just slip if traction is good. A test of how solid the vcu becomes when activated, if you like.

A good test you could do is drive up a 30 degree slow if you have one and you feel safe to do so. That would put more stress on the wheels as they need to grip the slope whilst moving the vehicle up the slope, which is heavier than normal due to it being on a slope, as your driving up hill and need to fight the pull of gravity more. If you film the rears spinning then that would indicate your vcu is working well, whilst under pressure, despite the one wheel up test being quick.

For eggsample this slope is 30 degrees and I have to drive towards and up it at about 1800 revs in first gear to get up it. I need traction control to activate to help me. All 4 wheels should be turning and tc will help reduce spinning wheels to maintain grip. Even if yours doesn't have tc you should get 4 wheels spinning at least. First slope at the start:

LRO Show 2010 part 1 of 2 Land Rover Freelander 1 v6 Off Road

LRO Show 2010 part 2 of 2 Land Rover Freelander 1 v6 Off Road

hmmm trying to think wheres close with a steep hill off road as its not like its going to be icy for a while lol

Those pictures look interesting. The weld seems quite neat so it doesn't look as if it's been re-welded. If I see correctly the first pic shows the fill hole at the top of the vcu has an unusual slight surface rust ring around it. As if something has been placed against it. That would make me wonder if you vcu has been "flushed" in some way to reduce the amount of liquid inside, which would support my guess of why the one wheel test completes so quickly - less resistance due less liquid inside. I've not tried doing this but met someone last year who mentioned it in conversation and said it takes a lot of air pressure to do, and way the easy "old style" of reducing vcu's performance.

matt1295 said:

hmmm trying to think wheres close with a steep hill off road as its not like its going to be icy for a while lol

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Grass slope?

Hippo said:

Grass slope?

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will start looking wheres suitable... shame i couldnt put some liquid in to see if it stiffens it up slightly

matt1295 said:

will start looking wheres suitable... shame i couldnt put some liquid in to see if it stiffens it up slightly

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You may find your vcu works well. Many reconditioners "loosen" then up with reduced liquid. Some betterer than others.

surely tho if its loosened up its not going to be as good if i go greenlaning

matt1295 said:

surely tho if its loosened up its not going to be as good if i go greenlaning

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It may be loose now but when in service and given constant grief when wheels are spinning etc you may find it still activates and works ok. As you have a vcu doing this it would be great if you can test it and help us out. If you do go off road make sure you have another vehicle with you and recovery ropes. Another vehicle and ropes is standard practice anyways.

Hippo said:

It may be loose now but when in service and given constant grief when wheels are spinning etc you may find it still activates and works ok. As you have a vcu doing this it would be great if you can test it and help us out. If you do go off road make sure you have another vehicle with you and recovery ropes. Another vehicle and ropes is standard practice anyways.

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yeah i will try it every couple of weeks and as soon as i can sort something out for a bit of greenlaning i will do it and report back now whos local to me lol

will test it as much and often as you want to because you have given me great advice and its my way of giving a little back to the forum

matt1295 said:

yeah i will try it every couple of weeks and as soon as i can sort something out for a bit of greenlaning i will do it and report back now whos local to me lol

will test it as much and often as you want to because you have given me great advice and its my way of giving a little back to the forum

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Thanks. Check it every 100 or 200 miles to see if anything is changing. I don't think it will change. If that's the case then up it a bit to every 500 miles. If it's still not changing the every 1000 miles. I find it easier to film the test to get a more accurate time.

My vcu has failed and I will continue with some additional tests. I spotted it starting to fail whilst testing. I plan to play with it some more but one option I haven't ruled out is trying to force some of the goo inside it out, then testing it again to see what the difference is.