Just been looking at some previous threads and noticed one which touched on the above.
Like the topic starter I have been looking for a method to resolve the problem of the failing Viscous coupling unit.
On the freelander the permanent 4wd system comprised an Intermediate reduction drive, a VCU and a rear diff. During normal road use this system delivers approx 75% of drive to the front wheels and 25% to the rear. When off road the VCU comes into play to try to give true 4wd performance.
Problems arise when the VCU either stiffens or totally siezes. When siezure occurs this causes transmission wid up and ultimately destruction of the rear diff and/or the IRD (very expensive) I understant that the life expectancy of these particular VCUs can be as low as 60K miles !!
No one seems to do an "improved" VCU so options are limited to preventative and relatively frequent replacement of the VCU or a solution similar to what the original poster was suggesting.
I have found that it is probably possible. In the US/Canada owners of the VW Vanagon Syncro were experiencing similar problems.
see below reply form one of their club members
""SDP made a few prototype Syncros with a decoupler instead of the VC. Although VW never sold any like this, it established the idea for the de-coupler. Patterned after the SDP prototype de-coupler several entrapenuers with machining skills and some parts from VW have built kits for sale. In the VW Syncro, the de-coupler replaces the nose cone of the transmission where the flange to the driveshaft comes out. In the de-coupler nose-cone is the mechanism to de-couple the output from the transmission so that no power is fed to the driveshaft which extends forward to the VC, the fron diff, and then to the front wheels. While de-coupled the VW Syncro is a rear-wheel-drive vehicle.
Check out one maker at:
I appreciate that there are differences, mainly that the VW becomes RWD whereas the freelander would become FWD.
Your advice/input/comments would be appreciated.
Chris
Like the topic starter I have been looking for a method to resolve the problem of the failing Viscous coupling unit.
On the freelander the permanent 4wd system comprised an Intermediate reduction drive, a VCU and a rear diff. During normal road use this system delivers approx 75% of drive to the front wheels and 25% to the rear. When off road the VCU comes into play to try to give true 4wd performance.
Problems arise when the VCU either stiffens or totally siezes. When siezure occurs this causes transmission wid up and ultimately destruction of the rear diff and/or the IRD (very expensive) I understant that the life expectancy of these particular VCUs can be as low as 60K miles !!
No one seems to do an "improved" VCU so options are limited to preventative and relatively frequent replacement of the VCU or a solution similar to what the original poster was suggesting.
I have found that it is probably possible. In the US/Canada owners of the VW Vanagon Syncro were experiencing similar problems.
see below reply form one of their club members
""SDP made a few prototype Syncros with a decoupler instead of the VC. Although VW never sold any like this, it established the idea for the de-coupler. Patterned after the SDP prototype de-coupler several entrapenuers with machining skills and some parts from VW have built kits for sale. In the VW Syncro, the de-coupler replaces the nose cone of the transmission where the flange to the driveshaft comes out. In the de-coupler nose-cone is the mechanism to de-couple the output from the transmission so that no power is fed to the driveshaft which extends forward to the VC, the fron diff, and then to the front wheels. While de-coupled the VW Syncro is a rear-wheel-drive vehicle.
Check out one maker at:
I appreciate that there are differences, mainly that the VW becomes RWD whereas the freelander would become FWD.
Your advice/input/comments would be appreciated.
Chris
