Haldex versus VCU

**Ausfree** · 3rd December 2011, 04:15 PM

OK, being the owner of a FL1 with a VCU system that appears to have a few problems,not mine but there has been many reported here.The FL2 has the Haldex system and I don't see anybody on this Forum complaining about problems with them. What is the difference?? why does the Haldex system seem superior to the VCU system???

aikendrum105 · 5th December 2011, 10:27 AM

Your post piqued my curiosity - and I found this:

[ame="http://en.wikipedia.org/wiki/Haldex_Traction"]Haldex Traction - Wikipedia, the free encyclopedia[/ame]

the '2006' section describes what the FL2 system does, seems as thought it's an electronically controlled hydraulically applied system - enabling drive to the rear to be on or off, or a proportion in between, decided by the computer, or manually via controls at the drivers behest.

The old VCU is a passive system with a silicon fluid within that allows slight differences in speed between the front and rear of the car - but a larger speed differential will cause it to lock - providing full 4wd. There's heaps of info on the forums about how/why they fail over time - early IRD ratios accelerating wear etc - you've probably read all that already

Thanks for bringing it up - I was curious myself !

Cheers,

**Ausfree** · 5th December 2011, 10:57 AM

Thanks mate, I didn't think of Wikipeadia!!!

ps. I notice at the bottom of the article in the section titled "Vehicles Equiped with Haldex" they do not mention LandRover Freelander 2????

**Ivan** · 5th December 2011, 11:08 AM

Originally Posted by Ausfree

Thanks mate, I didn't think of Wikipeadia!!!

ps. I notice at the bottom of the article in the section titled "Vehicles Equiped with Haldex" they do not mention LandRover Freelander 2????

It does under Tata Motors Land Rover LR2

Ivan

**Ausfree** · 5th December 2011, 05:55 PM

Originally Posted by Ivan

It does under Tata Motors Land Rover LR2

Ivan

Ooops!!

**101RRS** · 20th December 2011, 10:35 PM

When designing the FL1 Landrover had access to a perfectly good CDL system in the D1.

I don't know why they didn't just take the internal CDL arrangement from a LT230 - put it in a tube with a bearing at either end, bolt the tube to the chassis where the VCU is and activate the CDL via an electric solenoid. Vehicle would be proper Awd rather than front wheel drive with a bit going to the rear and when required lock the cdl for full 4wd.

I even bought a Lada Niva transfer case (dual range, constant 4wd with CDL) for $50 to build a replacement for the VCU but never got around to it.

Anyone want a Lada Niva transfer case?

Garry

aikendrum105 · 21st December 2011, 09:19 AM

I'd started thinking along the lines of a manual or electronic driveshaft decoupler on one side of the VCU - they usually work a little like the splined shaft with sleeve that the Vanagon Syncro's etc sometimes use - people with motorhomes fit them to their towed cars to decouple the propellor shafts while towing (more of an issue with automatic cars than manual I think)

Then I thought maybe just a simple flange / pins arrangment you could slide in / out - cover the whole thing up with a CV boot to keep it simple.

Even an eletromagnetic clutch arrangement like the old thermo-fans mounted on the waterpumps of cars used - just to pull it into mesh, not take the torque.

Either way involved shortening / welding the front or rear prop shaft to make room for it - but there's plenty of room under there for extra gear... But you still ended up with the Viscous buffer between the front / rear so the IRD didn't take all the pain when grip changed front / rear suddenly.

Also though of just opening a VCU - drilling 3 or 4 holes through the interlocking plates and using the same flange / pins idea to lock it up - but no give = toast IRD again perhaps....

Now that you can get the VCU for a reasonable price, reco or otherwise, it's less of an issue I guess - when they were highway robbery prices you'd do anything to get around paying for one... (like wait until your IRD explodes instead

)

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