Land Rover Repair: LAND ROVER freelander rear differential problem, land rover freelander, viscous coupling

Question
QUESTION: HI
I have 99 LAND ROVER FREEALANDER 2,0l tds DIESEL. I had problem with rear differential. At first it spreaded hard noise and pumped out all oil and the differential broke out. I have replaced it but after 2 month the problem has repeated. Differential pumped out the oil and crashed again. SO I replaced the differential and drive about 10 km and the noise in differential repeated again and it was very hot. WHere can be a prblem? Thank you in advance.

ANSWER: Different sized tyres could lead to differential failure.  Also, if the centre viscous coupling on the front to rear prop shaft is siezed, this could cause the differential to fail. Finally, if an incompatible unit has been fitted, e.g. incorrect ratio; one that does not match the front unit, this could cause these differentials to fail.

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QUESTION: How could I check if my viscous coupling working properly.

Answer
The best thing to do is put the car on full lock and drive it.  If it starts hopping instead of smoothly turning, this would be an indication of a seized unit.  

Another way to test it is to put the vehicle on a lift  (all 4 wheels off the ground) whilst in Park, with the hand brake off and see if you can rotate the rear half of the prop shaft with a pipe wrench.  If it is possible to rotate, even under some amount of force, it is fine.  If not, it is stuck.

I think the msot likely scenario for your vehicle is an incompatible front and rear differential units.