transfer case queries

[johnd]

a question to all you freelander experts out there:-

I understand that the (early) freebies had a suspect transfer case (IRD?) and viscous coupling. I understand also that if you are out from major centres and yours goes on you you can continue to drive until you reach somewhere to repair it by simply removing the rear tailshaft.
Is this an urban myth or is it correct?
when people say the transfer case fails what are they actually referring to? in my disco it would just get super noisy but still drive wh:confused:y are freebies different.
Sorry for the inane questions but I have a neice who wants one but is being warned off by well meaning friends with stories of dire consequences if the case fails.
If its a design fault do i assume most cars (1998 petrol) would have had it fixed by now?

Is there an aftermarket fix?

your advice will be appreciated, thanks

[Junosi]

Hi John, its no myth. Done it to mine in the interim until I get around to replacing the IRD and VCU(Viscous coupling). Effectively makes it a front wheel drive - bit pointless for a AWD freelander in the long term if you ask me but it works.

Freebies transfer case is different to your discos cause freebies are 'All Wheel Drive' instead of 4wd - most of the time its only front wheels that have power (well nearly all the power) - only when the transfer case detects front wheels slipping is power transferred to the rear wheels. The problem with the early freelanders was the diff ratios on the front and rear diffs were different by design and that difference was too large - which caused the VCU to work too hard and eventually fail - which takes out the IRD sooner or later. Later freebies they corrected the ratios to make the VCU do less work, mostly curing the problem.

If you're planning on removing the tailshaft more long term there's a guy in UK selling IRD blanking plates for the back of the IRD to make it more permanent.

Proper 'aftermarket' fix would be to fit an IRD from a later model freebie, chances are the VCU is snafu'd too.

Clark

[101RRS]

Very simply - the Freelander is basically a front wheel drive car that goes into 4wd automatically when the front wheels slip. Drive to the rear is basically a power take off from the front diff and it does not have a traditional transfer case. The front diff and rear pto unit is the IRD.

Most awd vehicles have differences in the front and rear diff ratios to enhance drivability and to activate 4wd quickly (this is done via the viscous coupling).

In early Freelanders this difference was too great and caused the VC to work overtime and after some time (100,000 - 130,000km?) the VC would fail and lock up so the Freelander was now contant 4wd with no way to relieve transmission windup - the load causes the PTO section of the IRD to fail - bearings give way making the crown and pinion in the PTO section to loose mesh. If nothing actually breaks and it is a bearing failure (ie nothing fails so the front diff is still intact) you may be able to drive after an IRD oil change and removing the rear drive shaft and VC. There is no load on the PTO and the damaged bearings are often able to cope with this.

The system does not fail overnight and if you regularly test the VC to detect its failure the rest of the system can be protected.

Later and replacement IRDs have a better front diff ratio and there is no problem. The above is a simplified version - but basically describes the system.

However - what would be a greater concern for me is the 1.8 petrol engine - they are a grenade and will fail - sooner or later - there is a fix but if it were me I just would not risk it. The IRD may have already failed and be fixed but even if it hasn't it can be monitored to detect failure before damage.

If it is a 1.8 petrol I would stay away.

There are plenty of threads on here about all the issues so have a look at those. Also on the IRD issue Ashcroft Transmissions (http://www.ashcroft-transmissions.co.uk/category_8.html)

There are fixes for the 1.8 engine and the fix for the IRD is to instal a new one or one out of a post 2000 model.

Garry