That's a strange one with the Power Steering.
I'd pay attention to the way the brakes feel. Maybe the hydroboost accumulator is doing something strange but I can't see it holding enough fluid to overflow the reserviour.
I'd be tempted to flush the power steering system out with fresh power steering fluid to get rid of any contaminants in the Hydroboost and the rest of the system. The filthy fluid I flushed out of my truck was somewhere between brown and black. It wasn't as nasty when I checked on it after a month but it was dark so I flushed it again.
If you tie a transmission fill funnel to something you will not have to reach down next to the fan to pour fluid in the pump with the engine running.
All of the 2500HD trucks use a close enough to the same hydroboost system.
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1959 M35A2 LDT465-1D SOLD
1967 Dodge W200 B383, NP420/NP201 SOLD
1969 Dodge Polara 500 B383, A833 SOLD
1972 Ford F250 FE390, NP435/NP205 SOLD
1976 Chevy K20, 6.5L, NV4500/NP208 SOLD
1986 M1008 CUCV SOLD
2000 GMC C2500, TD6.5L, NV4500
2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263
2009 Impala SS LS4 V8
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