Re-oil the turbo before installing or running, or the bearings won't survive. Fill the oil inlet with motor oil and spin turbo -- I'm betting the "stiffness" will return (full floating frictionless bearings -- they don't spin freely unless full of warm oil).

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!