Freelander 1 HCU - Hippo Coupling Unit (TM)

Keep the VCU of course. At the mo' the VCU is constantly slipping due to the different ratios front and rear, thus front prop wants to turn at a different speed than the rear. Because the wheel speed is the same, the difference is taken up by the VCU, but this gives a fwd bias and feel, so that the 'normal' people who bought them first time around felt like they were driving their old boring hatches. Anyway, this constant slipping is possibly one thing that helps an early grave of the VCU as it is always 'under tension' as is the rest of the drive train. Now, if it was equal gearing front and rear, then both props more or less the same speed (in a straight line) so no constant loading and early grave of the VCU which means no loading of the diff or IRD. Of course, slip the front wheels, and the rear will kick in as normal.

This is why LR changed the ratios as the Freelander evolved to try to reduce the difference front/rear, with some success, but they still kept the fwd bias. The RR is 50:50 and AFAIK does not suffer the same probs as us. Am I right in the RR bit?

Spacemonkey... said:

Keep the VCU of course. At the mo' the VCU is constantly slipping due to the different ratios front and rear, thus front prop wants to turn at a different speed than the rear. Because the wheel speed is the same, the difference is taken up by the VCU, but this gives a fwd bias and feel, so that the 'normal' people who bought them first time around felt like they were driving their old boring hatches. Anyway, this constant slipping is possibly one thing that helps an early grave of the VCU as it is always 'under tension' as is the rest of the drive train. Now, if it was equal gearing front and rear, then both props more or less the same speed (in a straight line) so no constant loading and early grave of the VCU which means no loading of the diff or IRD. Of course, slip the front wheels, and the rear will kick in as normal.

This is why LR changed the ratios as the Freelander evolved to try to reduce the difference front/rear, with some success, but they still kept the fwd bias. The RR is 50:50 and AFAIK does not suffer the same probs as us. Am I right in the RR bit?

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yes , they still seize eventually but usually at higher mileages than fl,but then even when they do theres less strain on system and often people dont realise ,as it is equal speed of drive to both axles,so effect less ,though they eventually do take front diff out

Spacemonkey... said:

Keep the VCU of course. At the mo' the VCU is constantly slipping due to the different ratios front and rear, thus front prop wants to turn at a different speed than the rear. Because the wheel speed is the same, the difference is taken up by the VCU, but this gives a fwd bias and feel, so that the 'normal' people who bought them first time around felt like they were driving their old boring hatches. Anyway, this constant slipping is possibly one thing that helps an early grave of the VCU as it is always 'under tension' as is the rest of the drive train. Now, if it was equal gearing front and rear, then both props more or less the same speed (in a straight line) so no constant loading and early grave of the VCU which means no loading of the diff or IRD. Of course, slip the front wheels, and the rear will kick in as normal.

This is why LR changed the ratios as the Freelander evolved to try to reduce the difference front/rear, with some success, but they still kept the fwd bias. The RR is 50:50 and AFAIK does not suffer the same probs as us. Am I right in the RR bit?

Click to expand...

Yeh sounds good to me, and of course again comes back to the issue of tyres and that by ensuring as much as possible that tyres are same and tread depths kept close between front and rear then this constant slipping should be avoided or at least limited as much as possible. As I posted before im fitting new vcu tommorrow and my current one is the original having done 110k miles. I bought it at aroubd 80k with all different tyres which I changed right away for 4 matching ones. Im now on 2nd matching set. My vcu seems not too bad, definitely not seized and im sure its only my tyres OCD that has protected the rest of my transmission until now. I wasnt being ignorant on vcu mileage, just didnt know until I read it on here that they only good for around 70k.

That 70k will open a can of worms....

Would ya believe I just found out my brother works for Titan? FFS

Spacemonkey... said:

That 70k will open a can of worms....

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Lol, probably. Its what drew my attention to the whole vcu issue. Altho my decision to renew is based on one wheel up test showing things a bit tight. Didnt drag it out too long tho, round this neck of the woods, and coming up xmas, got to get ma one wheel back on the ground before someone robs the other 3.:lol:

I'm in the 'change it every 70k just in case, but check it fairly regularly before' camp, but others disagree. Some last 5 minutes, some last forever, but few really seem to last over 100k. Personally, considering the cost of a new VCU, I think it's cheaper than an IRD, diff etc etc....

Agree, exactly what I thought and changed it because I had doubts. 250 quid is a fair bit of cash but nothing on the potential cost of failure. Recon vcu fitted today and I do feel a difference. Findings posted in vcu testing thread.

110k miles... interesting.

We're not completely sure how the vcu ages. Some say if it's not used (read as exercised oft road) regular then they age quicker. Higher the age, then worse they become. They also go on to say those which do many motorway miles are more likely to fail... from first hand testing the vcu gets hotter at higher speeds over the same route/distance, when compared to doing the same trip at lower speeds. A common problem is heat. If the vcu gets too hot on a regular basis this will age them quicker we beleive. Bad tyres (mismatched make/model/size) is a big cause of this and is a risk. Also incorrect pressure tyre (lower pressure = more grip and the vcu works a bit harder as there's no tyre slip to give it some relief if needed) and running on a flat tyre is also a problem.

My advice for someone with a 110k miles vcu would be to test it to see what it's like. vcu's give differing results. If someone tests theirs regular and see's a change, then they know something is happening and can react if required (what I did). It's said to be impossible for it to get to such a high mileage but many have. We're never sure if balance of tyre factors etc has helped this as we often don't know the history. If your worried then it's well over the expected guess of it's life time, and well into the after life too. So changing it twice would correct this. One Wheel Up Test and Turnip Test is yer friend.

Mine was at 120k when it was changed, mostly motorway miles.
Having said that I was very careful with tyres etc.
Also the car had 54k on it when I bought it, so I assume it was the original.
When it finally went, it seemed to fail fairly quickly.

It was only reading the appropriate threads on here which I think saved me. There has always been some tightness on full lock but I assumed it was normal, for a 4wd. I was all set to do a one wheel up test with old vcu but the weight I had to put on my 1m bar to move it was well, in excess of 5 to 10kg so I didnt bother. Recon unit was more suitably slack , 25ish secs with 5kg on 1.2m bar ( recorded in test thread) . Im assuming it was original vcu as it was an 03 stamp on my 03 plate td4 and bearings looked old. Replacement is stamped as an 01. I definitely I will be making regular checks now. I have no idea what previous owner did with car but they werent fussy about tyres.