Just saw this thread.
With any AWD system, the front and rear diffs should all be spining at the same speed.
Of course there is a bit of slack, but when you replace new tyres on the front and old tyres on the back, the wheel rotation speed is significant enough to cause problems. It will do is heat the oil to a certain level that causes a sensors to go off. Hence the 4WD light that people are talking about.
If you continue to drive on the light, there is a good chance you will break both the front and rear diffs in the car. Trust me, i've seen it happen to my cousin's MPS 6 and it ain't pretty. If you get this light on the MPS6 and you've only changed 2 tyres, go back and buy 2 more!
Either that, or get a grade of oil for the rear diff that supports high temperatures.(and put it in the diff that has the smaller wheels attached)
Like nissanman's post above, you have to rotate the tyres every 10-15k, and when you replace tyres, replace all 4 at once. Buying 2 can cause serious problems(and when it's not covered under warranty it's costly!)
Last edited by lazydog; 16-09-2009 at 04:41 PM.
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