The 98-00 XC70 has a number of faults, mainly in the AWD running gear.

1-The drive shaft is seriously expensive to work on and obscene to replace
2-The front hubs/bearings have a tendency to wear unevenly which places unequal stress on the transfer system which means it wears out faster.
3-The entire AWD system runs on a viscous cluth system that means you MUST have both tires on one axle be within .5% of round or the infamous "bevel gear" wears out which means an expensive replacement rebuild of the rear transfer box.
4-The AC system is known for bad evaporators. Replacement is a 10 hr labor charge

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