The OE harmonic balancer failed at 100K miles on the 98 Montana. By failed I mean the outer pulley had moved outward causing belt misalignment. It still drove the various assecessories OK. I replaced it with a Dorman unit that lasted 3 weeks and 2200 miles. It completely failed with the outer pulley completely uncoupled from the inner hub. There's no apparent misalignment in the drive pulleys or does there appear to be excessive drag when the a/c compressor engages. Anyone have multiple harmonic balancer failures? or stated another way...... any experience with "made in China" aftermarket units and their failure rates?