What causes failure in ird unit of freelander?

Answer 1

The best answer to this question I have ever seen is on http://www.ashcrofttransmissions.co.uk/category_8.html It reads: QUOTE The Freelander has 3 main drivetrain problems areas, the Intermediate Reduction Drive (IRD), Viscous Coupling (VC) and the rear differential. The reason for this is the front wheels on the Freelander are driven faster than the rear wheels so it handles well, like a front wheel drive car. To accommodate this ratio difference, a VC is fitted inline with the rear propshaft which thus is constantly slipping. On the earlier models this ratio difference was too great resulting in the viscous coupling working overtime and failing by siezing solid. When the viscous coupling is too tight or seized solid the front tyres are fighting the rears as the transmission is "winding up", initially this just wears the tyres (causing a "saw tooth" effect) but it also puts increased load on the IRD and rear diff as they are fighting each other causing rapid wear on both and ultimately failure of one or both. UNQUOTE The source of this comment is the Ashcroft Transmissions website.