P38A About that VCU thingy.

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Yes but it takes ages, about 70k miles on average, yet I've read that driving with a tyre more worn than its axle mate or a few lbs of pressure difference will cause harm within a couple of hundred miles. I know I'm not Einstein but the claim doesn't ring true.

Col
Different rolling radius's just put additional strain on the VCU causing earlier failure but not within a couple of hundred miles.
 
The thing about vcu lore that confuses me is, us freelander owners are constantly warned of the perils of having mismatched tyres, tyres with differing tread wear and tyres with different pressures. The reason being from what I gather is that unless the tyres are all the same diameter they will revolve at slightly different speeds and so goose the vcu. Well, it seems to me that most of my driving is not on straight roads, much more than 50% of my overall mileage is around town. So my tyres are revolving at different speeds relative to each other much of the time, so why doesn't that wreck the vcu?

Col

The front and rear diffs on the Freelander have different ratios. The rear wheels through forward motion drive the rear prop faster than the front prop to keep the VCU active, so basically it is front wheel drive. If the front wheels lose traction then the front prop rotates faster than the rear prop giving four wheel drive as the VCU locks up.
 
When I first got my freelander I had read the warnings about mismatched tyres, which mine had, so the first thing I did was put 4 new tyres on it. The spare is about 50% worn and now it's a different make to the new ones. I've had this fear that if I needed to use the spare it might cause damage to the vcu but thinking about it, I don't think that would be the case. Yes, I agree tyres with a slightly different diameter will put extra strain on the vcu but not excessively so, especially if the vcu is in good condition.

Col
 
When I first got my freelander I had read the warnings about mismatched tyres, which mine had, so the first thing I did was put 4 new tyres on it. The spare is about 50% worn and now it's a different make to the new ones. I've had this fear that if I needed to use the spare it might cause damage to the vcu but thinking about it, I don't think that would be the case. Yes, I agree tyres with a slightly different diameter will put extra strain on the vcu but not excessively so, especially if the vcu is in good condition.

Col
It will put extra strain on the diff on the axle with different tyres, but short term I wouldn't worry about it.
 
No transmission jack needed to change the VCU, it's behind the front cover on the transfer box where the front prop connects.

That's true, I replaced the lot. I figured the Morse chain had done over 150k miles (Land Rover reckon replace at 100k) and for a couple of hundred extra quid I was future proofing against future niggles. I think that also was worthwhile as the car would lurch going down steep hills in gear as the slack in the chain snatched. It no longer does that.
 
That's true, I replaced the lot. I figured the Morse chain had done over 150k miles (Land Rover reckon replace at 100k) and for a couple of hundred extra quid I was future proofing against future niggles. I think that also was worthwhile as the car would lurch going down steep hills in gear as the slack in the chain snatched. It no longer does that.
No excess slack in the chain the I can detect in either of mine at well over 100K, I assume yours is a manual gearbox? Auto would tend to mask any back lash and also put less strain on the chain.
 
No excess slack in the chain the I can detect in either of mine at well over 100K, I assume yours is a manual gearbox? Auto would tend to mask any back lash and also put less strain on the chain.

Yes, manual. You only noticed it on steep hills. Mine does a bit of offroading and towing so works fairly hard.
 
Range Rovers are full time four wheel drive. Freelanders are front wheel drive with part time four wheel drive. The set up is totally different, sticking a VCU in the drive to the rear wheels was a cheap compromise for the Freelander. Land Rover should have listed it as a serviceable item. That set up was always going to cause problems.
 
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