Possible vcu fault

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Vickyb

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I have a 2003 freelander td4 estate. I had a towbar fitted to tow a single horse box and a small caravan. I have towed with it twice (caravan) and on both occasions within 20 miles the seal on the rear diff has blown. It also performs poorly in muddy/icy conditions.

I have been told that its a faulty vcu which is distributing too much load to the rear diff under load and also causing issues in poor weather conditions (it slides like a rear wheel drive). It's done 99k, I have a full service history but can't see that the vcu has been changed at 70k as recommended.

Is the cause of my towing issues the vcu or is something else at fault. I know I need to change the vcu anyway due to mileage but do I need to be looking elsewhere as well?
 
take no notice of the rude tratters , if the vcu has given up then you would not get any drive to the rear wheels, it is more likly to be the diff but have it checked out some idiot might have done some sort of mod on the vcu , i have never heard of one doing what yours is.but maybe someone on this freelander site may know more than me. hope this helps.
 
Teddy is talking rubbish I'm afraid, ;) most vcu failures cause too much strain on drive line as its too tight not too soft. You have 3 possible issue, or a combination of them

1. Vcu is too tight
2. The extra weight on the rear of the car when towing has reduced the the rear tire rolling radius, causing the vcu to slip more, heat up and become tighter.

3. Mismatched tire sizes

These issues can cause the rear diff to over heat, usually melting the breather pipe, pressuring the rear diff and popping the diff seals.

As its not happening when driving normally I'd say its the rolling radius issue caused by the extra weight, but this maybe being compounded by a tight vcu and possible mismatched tires due to wear/make/size
 
thank you Austen for your words of wisdom. Forgive my ignorance, what should I do about a rolling radius issue? I was planning on replacing the vcu and I can look at the tyres although I have a full set of matching tyres on there.
 
Vickyb said:
thank you Austen for your words of wisdom. Forgive my ignorance, what should I do about a rolling radius issue? I was planning on replacing the vcu and I can look at the tyres although I have a full set of matching tyres on there.
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Tyre wear affects the rolling radius :), check for different amounts of wear between the fron and rear tyres. It is highly sensible to rotate your tyres every 3-5k so that they wear at a perfectly even rate. But listen to Austen, he is a professional in this field and by far the best transmission guy on this section ;).
 
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Vickyb said:
thank you Austen for your words of wisdom. Forgive my ignorance, what should I do about a rolling radius issue? I was planning on replacing the vcu and I can look at the tyres although I have a full set of matching tyres on there.
Click to expand...

Make sure the rear tires are at the correct pressure for towing and make sure the trailer nose weight is correct. Both of those will effect the rolling radius of the tyres ;)
Also make sure the rear tyres have the most tread!!
 
Are tires all same make and model and worn the same?

You need to increase rear tire pressure when towing to stop tires compressing.

Check temp of vcu after a few miles of a relatively straight journey. Luke warm to the touch is the hottest you want.

Was there a smell of gas when seals popped? If you can check breather pipe where it goes into diff see if its melted, but its hard to see
 
Suddenly I'm glad I don't have osses. Tbh it seems like ossboxes are a bit too much for your average hippo :(, I've seen alot of issues relating to towing here. Like the guys said, you need to be on top of things like pressure and wear or you will run into problems in short order - as you have found :).
 
Just read about rear drive issue/slide, have you Defo got front wheel drive?? Just wondering if you only have rear drive due to gearbox fault, and all that extra weight when towing is overloading rear diff. Doubt it as I'd have thought it would cause issue with rear diff. Just something else to check
 
austen said:
Just read about rear drive issue/slide, have you Defo got front wheel drive?? Just wondering if you only have rear drive due to gearbox fault, and all that extra weight when towing is overloading rear diff. Doubt it as I'd have thought it would cause issue with rear diff. Just something else to check
Click to expand...

That would explain the poor mud/snow performance. Mine is like a mountain goat in those conditions so there's gotta be a problem there.
 
There was a very strange smell when it went. Ive replaced it so not sure about breather pipe.

I havent towed a horsebox with it, it was a small caravan but in any event the horsebox is only a single one with a mam of 1400kg so shouldnt be a problem.

I see what you are saying about the front drive, I understand that gear box problems can arise as a result of the vcu issues? Im beginning to wonder if its not more trouble than its worth as I presume a gearbox problem will be expensive to fix :(

p.s thank you for taking the time to read my ignorant posts and reply!
 
Tis not the gearbox usually, it's the IRD. If you look up Bell Engineering's website there is a whole section explaining how the common problems happen - you can also search here but there will be hundreds of threads to sort through!
 
austen said:
Teddy is talking rubbish I'm afraid, ;) most vcu failures cause too much strain on drive line as its too tight not too soft. You have 3 possible issue, or a combination of them

1. Vcu is too tight
2. The extra weight on the rear of the car when towing has reduced the the rear tire rolling radius, causing the vcu to slip more, heat up and become tighter.

3. Mismatched tire sizes

These issues can cause the rear diff to over heat, usually melting the breather pipe, pressuring the rear diff and popping the diff seals.

As its not happening when driving normally I'd say its the rolling radius issue caused by the extra weight, but this maybe being compounded by a tight vcu and possible mismatched tires due to wear/make/size
Click to expand...
i said some one may know better but i personal have never heard of this one before
 
WLJayne said:
Tis not the gearbox usually, it's the IRD. If you look up Bell Engineering's website there is a whole section explaining how the common problems happen - you can also search here but there will be hundreds of threads to sort through!
Click to expand...
Austen is Bells engineering say no more, I bow to his more knowledge than mine on this issue i am still learning about Freelanders all the time when i started as a mechanic i worked on side valve engine not these modern over head cam ones, but tell me did the funny smell, smell like gas
 
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Vickyb said:
There was a very strange smell when it went. Ive replaced it so not sure about breather pipe.

I havent towed a horsebox with it, it was a small caravan but in any event the horsebox is only a single one with a mam of 1400kg so shouldnt be a problem.

I see what you are saying about the front drive, I understand that gear box problems can arise as a result of the vcu issues? Im beginning to wonder if its not more trouble than its worth as I presume a gearbox problem will be expensive to fix :(

p.s thank you for taking the time to read my ignorant posts and reply!
Click to expand...

Its less likely to be the gearbox, it was only you saying its was squirrelly at the rear that made me suggest it was rear wheel drive only. If you take the rear wheels off the ground and just try the biting point of the clutch, If the car tries to move gearbox is fine. If its only rwd then its the differential in the gearbox, we can change juat that part for less than a price of a recon ird. Just once we have seen rwd only and it was the ird, but you can check that by looking through fill plug of ird to see if the gears have teeth on, but like I say only every seen that once, usually when those years go the ird splits in half at the same time.

It most likely just vcu or/and tires diameters, so don't panic, yet ;) you say you changed the diff after the first time it happened, how long did it take for it to blow the seals the 2nd time??

Burnt transmission fluid stinks of gas, so much so we had the gas board called out to our road when I left rags soaked in burnt oil in our dustbin for collection, funny thing is we don't even have gas in our town, lol!
 
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