R

ragsyrandell

New Member
I've been having problems when on full lock. Getting transmission wind up then a clunk. Seemed to be ok when driving straight so i assumed a VCU problem. I've taken the front prop off and its now going fine. Having read a few lines about how a vcu works, if i understand it; there are plates inside with a gel type substance which increases in viscocity when agitated / heated up. This then gives you the 4 wheel drive. Now i've disconnected the front prop is the gel likely to return to its former glory or is it knackered. Sorry, should have said that i think the problem arose from different size tyres. I had 255x60xR18's on front (low tread) and brand new 255x55xR18's on back. I was advised that this would be fine but i'm assuming it wasn't. If it is knackered, is it a big job.
 
new tyres should always go on the back.

VCUs do not repair themselves. it is knackered.

contact BELL.
 
Fitting tyres with a different rolling radius on the front and back is daft. Why did you ever do that? VCU will need changing.
 
The thought was a worn (3-4mm tread) 255 60 18 tyre would be the same rolling circumference as a brand new (7-8mm tread) 255 55 18. Sounds really stupid now but when i was told it seemed to make sense. Anyway moving forward, Is the VCU part of the flange that that the front prop bolts to and if so can it pull out or is it a transfer box out job.
 
ragsyrandell said:
The thought was a worn (3-4mm tread) 255 60 18 tyre would be the same rolling circumference as a brand new (7-8mm tread) 255 55 18. Sounds really stupid now but when i was told it seemed to make sense. Anyway moving forward, Is the VCU part of the flange that that the front prop bolts to and if so can it pull out or is it a transfer box out job.
Click to expand...

In theory they should be ok in that instance but it's not good practice to do it. VCU is in the casing on the transfer box held by six bolts and yes the drive flange attaches to it.
 
ragsyrandell said:
I've been having problems when on full lock. Getting transmission wind up then a clunk. Seemed to be ok when driving straight so i assumed a VCU problem. I've taken the front prop off and its now going fine. Having read a few lines about how a vcu works, if i understand it; there are plates inside with a gel type substance which increases in viscocity when agitated / heated up. This then gives you the 4 wheel drive. Now i've disconnected the front prop is the gel likely to return to its former glory or is it knackered. Sorry, should have said that i think the problem arose from different size tyres. I had 255x60xR18's on front (low tread) and brand new 255x55xR18's on back. I was advised that this would be fine but i'm assuming it wasn't. If it is knackered, is it a big job.
Click to expand...
If the VCU is not knackered, it soon will be driving without the front prop.
The VCU does not give you four wheel drive, it locks the centre diff when required.
You can test the VCU by putting a bar on the front diff flange It should turn with some effort, if it's locked solid it's duff and you can safely drive with the prop removed.
 
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