Tires: tire sizes effecting a transfer case, goodyear dealers, tire diameters

Question
I have a 2002 Mercury Mountaineer.
2 years ago we replaced two back tires
at the Goodyear dealers.  Every other
repair has been with my local Mecury dealer.
This week they have told me that my
transfer case was bad and needed to be replaced, due
to the fact that the front tires were smaller than the
back tires and which made the front tires spin faster
than the back.  I just don't understand how this mistake
could have been made and that over the 2 years no
one would have caught this.  Can you explain to me what
the transfer case does?

Thanks

Answer
Julie,

I'm sorry to tell you but as the owner of the vehicle, the primary responsiblility for this rests with you.  I am sure you requested to the tires 2 at a time - and the tire dealer was happy to comply.  The dealer probably should have informed you this was a bad idea, but this is difficult for the average motorist to accept - plus there was a certain probablility that this might not have caused a problem.

What happened is that the tranfer case provides power to both the front and the rear tires when the 4X4 mechanism is activated.  If the tire diameters are different - and they usually are if the tires are different - the transfer case tries to cope with the difference by tearing itself apart.

Sorry for your loss, but this is an experience that you should pass onto others