Mine did the same thing and I ended up replacing both. They were originals with 230K+ on them, which is a pretty good sevice interval IMO. It's not a bad job to DIY.

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1983 240D - For Sale!
1994 Ford Bronco - Awaiting a refresh
2012 Jetta TDI - Wife's MPG machine
2002 BMW M3 - Weekend/track toy
2014 Ford Fiesta ST - DD